Caramelized Onions and Mushrooms Roast Dinner

This Caramelized Onions & Mushrooms recipe turn any roast into something extraordinary and can be cooked entirely ahead to save time!  This is a Pork Tenderloin roast, but you can use beef or chicken too.

Irresistible.  Mouthwatering.  Addictive.  Even…Sexy.  Yes, friends, I am describing my Caramelized Onions & Mushrooms that turn any roast into something extraordinary.  The Caramelized Onions & Mushrooms are sauteed low and slow with lots of love to bring out all of the natural sugars and caramelize them to perfection.  If that wasn’t enough, a touch of balsamic vinegar at the very end takes them over the edge.  

I served this on a roast pork tenderloin that’s moist and juicy on the inside and seasoned perfectly on the outside as it roasts simply in the oven.  But you could serve this with a beef roast, lamb roast, or a sneaker and it would taste great (too far?)!  

Simple Ingredients for this Pork Tenderloin with Mushrooms and Onions

• Pork Tenderloin
• Extra Virgin Olive Oil
• Yellow Onions
• White button Mushrooms (or Cremini)
• Butter or Ghee
• Balsamic Vinegar
• Seasonings: Dried Oregano, Garlic Powder, Onion Powder, Ground Pepper, Salt

Easy Caramelized Onions and Mushrooms!  A Little Time, A Lot of Love

Caramelizing onions take a little bit of time and lots of love.  But if you do it, you will be so happy!!  The taste is unbelievable.  Your family and friends will love you even more.  You may even see unicorns and rainbows.  The truth is, these are simple to make, so PLEASE TRY THIS RECIPE!  Caramelized Onions & Mushrooms are so special, not only are they great on Pork Tenderloin, but would be fantastic on just about anything…chicken, beef, potatoes, roasted veggies, flatbread, toast…I could go on and on.

This Video shows you how easy the recipe is

Sides to Serve with a Roast

If you make these Caramelized Onions and Mushrooms and serve over a roast pork (or beef or other), here are some equally delicious side dishes that would be fantastic with it.  Let’s start with a healthier side that tastes great with a little caramelized onions and mushrooms on top, my Light and Easy Roasted Garlic Cauliflower Mash.  It tastes just like mashed potatoes, but healthier! 

Or a more traditional side is my simple Sage Butter Potatoes Side Dish.  If you want a decadent make-ahead side, try my Cheesy Hash Brown Casserole. 

And finally, sticking with the mushroom theme, how about Mushroom Quinoa Risotto?

For a veggie, you could just do simple Roasted Carrots with Cumin or Green Salad with Honey Shallot Vinaigrette and Herb Parmesan Crisps

Quick note!  This post contains affiliate links, which means I earn a commission (at no extra cost to you) if you purchase from them.  This commission is what helps me keep this blog afloat :).  But, I also share these links because I have used the products, genuinely love them, and want you to know exactly what I used. 

PREP-AHEAD STEPS FOR YOUR PORK TENDERLOIN ROAST

Ok, let’s face it, this recipe is really all about the onions.  The onions are the stars here.  The mushrooms play a key supporting role in adding depth to the flavor, as well as meatiness and texture.  The pork tenderloin, while delicious, is really just an extra in this show.  You could certainly replace the pork with chicken, beef, or potatoes.  However, I do love the presentation of a sliced lean pork tenderloin roast with the onions and mushrooms draping all over the top so beautifully.

You can make the Caramelized Onions & Mushrooms a day or two ahead and store them in the fridge or make them while you cook the pork tenderloin.

I used two medium onions in this recipe.  Combined with the mushrooms, this is plenty.  However, if you eliminate the mushrooms, add another onion or two.

Peel the onion, slice in half, then thinly slice.  Slices should be about the width of the chefs knife.  Once they are all sliced, separate the onions with your fingers.

To a large preheated skillet or frying pan over medium heat, drizzle the olive oil and then add the onions.  Stir to coat in the oil, add salt and pepper.  Cook the onions on medium-low heat for 20 minutes, stirring every 5 minutes or so.  

For the mushrooms, you can either buy them already sliced or whole and slice them yourself.  

Push the onions over to one side of the skillet and add the Ghee or butter and then the mushrooms.  If you have never used Ghee, it is clarified butter which means that the milk is separated from the fat, so it is better for those with dairy sensitivities.  I love the 4th and Heart brand.

Saute the mushrooms for 10 minutes until browned.  Then mix the onions and sauteed mushrooms together, add the oregano and balsamic vinegar, and cook down for a final 10 minutes.

At this point, you can keep it warm or save it in a glass storage container in the fridge so that you can reheat it later.  

Cooking Steps for you Caramelized Onions and Mushrooms

I really like the pork tenderloin here as it’s a lean protein, the tenderloin roast can feed several people and slices so beautifully, and it has a mild flavor so that it doesn’t compete with the delicious Caramelized Onions and Mushrooms.

To start, you will need to season the tenderloin.  I make my own spice rub with Dried Oregano, Garlic Powder, Onion Powder, Salt, and Pepper.

Spray or rub all sides of the pork tenderloin with extra virgin olive oil, then sprinkle and rub the seasoning all over the outside. I love my Sonica Organics Oil Sprayer for this because it is non-aerosol (no toxins and propellants) and is so easy to pump, then spray evenly across all of the slices without using too much.

Then place the tenderloin under the broiler for 5-8 minutes until the top is nicely browned.  Move the pork down to the center rack and cook at 400 F degrees for 10-15 minutes or until the internal temperature reaches 145 F.

When the pork is done cooking, let it rest for 10 minutes tented with aluminum foil to allow the juices to redistribute.  Then slice the tender pork tenderloin and serve with the Caramelized Onions and Mushrooms.

Caramelized Onions and Mushrooms Recipe FAQs

Can I use pork chops instead?

Yes, I would actually sear them in the pan first, before starting the onions. Season the pork chops with salt and pepper on both sides liberally. Preheat a large skillet on high heat and add 2 teaspoons of Extra Virgin Olive Oil to the skillet to coat and then add the pork chops to sear. Leave cooking without moving for 4-5 minutes. When they easily lift, flip the chops over to sear the other side for another 4 minutes.  Transfer them to the oven and bake at 400 F degrees for 10 minutes.

What other Roasts can I make with this instead of Pork?

Yes!  You can make a variety of beef roasts, lamb roast, even a vegetarian cauliflower head roast!  For beef, I suggest a Beef Tenderloin roast, but there are many options.  Here is a great resource for various beef cuts and cooking times.  If you want to go the lamb route, I suggest a boneless leg of lamb roast.  

What Vegetarian option can I serve this with?

Roast Cauliflower Head!  It’s an impressive presentation and goes great with the full flavor that you get from the caramelized onions and mushrooms.  Here is a super simple recipe for roasting a whole cauliflower head in the oven.

Can I use regular butter instead of ghee?

Of course!  Just use 1 tablespoon unsalted butter.

Can I add wine instead of balsamic vinegar?

You can replace the balsamic vinegar with a dry red wine.  Add about 2-3 tablespoons of red wine along with a teaspoon of honey.  Let the alcohol cook out of the wine for the 10 minutes indicated in the recipe.  

How far in advance can I make this?

You can make the caramelized onions and mushrooms up to 4-5 days in advance and store them covered in the fridge.  I would make the pork tenderloin when you are ready to serve.  Simply reheat the onions and mushrooms in a pan on the stove for about 5 minutes until warmed through.

Can I freeze the caramelized onions and mushrooms?

Yes, you can freeze the caramelized onions and mushrooms in an airtight container in the freezer for up to 6 months.  Thaw them in the refrigerator overnight and then reheat the onions and mushrooms in a pan on the stove for about 5 minutes until warmed through.

Have you tried this recipe? If so, please leave a ⭐️⭐️⭐️⭐️⭐️ star rating in the recipe below! I love to hear your feedback and your rating helps others to find this recipe. Thanks so much!

5 from 1 vote

Print

Caramelized Onions & Mushrooms on Pork Tenderloin

Caramelized Onions & Mushrooms on Pork Tenderloin is such a flavorful main dish!  The pork tenderloin is moist and juicy and topped with Onions & Mushrooms that are sauteed low and slow with a touch of balsamic to bring out all of the natural sugars and caramelize them to perfection.

Course Main Course

Cuisine American

Keyword christmas dinner, dinner, mushrooms, onions, pork, pork roast, pork tenderloin

Prep Time 15 minutes

Cook Time 40 minutes

Total Time 55 minutes

Servings 4 Servings

Calories 305 kcal

Author Carrie Tyler

Ingredients

Pork Tenderloin

• 1 pound Pork Tenderloin
• 1 teaspoon Extra Virgin Olive Oil
• ½ teaspoon Dried Oregano
• ½ teaspoon Garlic Powder
• ½ teaspoon Onion Powder
• ½ teaspoon Ground Pepper
• 1 teaspoon Salt

Caramelized Onions & Mushrooms

• 2 Tablespoons Extra Virgin Olive Oil
• 2 Medium Yellow Onions
• ½ teaspoon Salt
• ½ teaspoon Ground Pepper
• 1 Tablespoons Ghee or Butter
• 8 ounces Sliced Mushrooms
• 1 Tablespoons Balsamic Vinegar
• 1 teaspoon Dried Oregano

Instructions

1. You can make the Caramelized Onions & Mushrooms a day or two ahead and store them in the fridge or make them while you cook the pork tenderloin.
2. For the mushrooms, you can either buy them already sliced or whole and slice them yourself.
   
3. Peel the onion, slice in half, then thinly slice. Slices should be about the width of the chefs knife.
   
4. Once they are all sliced, separate the onions with your fingers.
   
5. To a large preheated skillet, drizzle the olive oil and then add the onions. Stir to coat in the oil, add salt and pepper. Cook the onions on medium-low heat for 20 minutes, stirring every 5 minutes or so.
   

6. Push the onions over to one side of the skillet and add the Ghee or butter to the open space and then the mushrooms. Saute the mushrooms for 10 minutes until browned. 

   

7. Then mix the onions and mushrooms together, add the oregano and balsamic vinegar, and cook down for a final 10 minutes.

   
8. At this point, you can keep it warm or save it in a glass storage container in the fridge so that you can reheat it later.
   
9. Make the pork spice rub by adding to a small mixing bowl, the Dried Oregano, Garlic Powder, Onion Powder, Salt, and Pepper. Stir to combine.
   
10. Spray or rub all sides of the pork tenderloin with extra virgin olive oil, then sprinkle and rub the seasoning all over the outside. Then place the tenderloin under the broiler for 5-8 minutes until the top is nicely browned. Move the pork down to the center rack and cook at 400 F degrees for 10-15 minutes or until the internal temperature reaches 145 F.
    
11. When the pork tenderloin is done cooking, let it rest for 10 minutes tented with aluminum foil to allow the juices to redistribute. Then slice the pork and serve with the Caramelized Onions and Mushrooms.
    

Recipe Video

Recipe Notes

1. Substituting Pork chops: Sear them in the pan first, before starting the onions. Season the pork chops with salt and pepper on both sides liberally. Preheat a large skillet on high heat and add 2 teaspoons of Extra Virgin Olive Oil to the skillet to coat and then add the pork chops to sear. Leave cooking without moving for 4-5 minutes. When they easily lift, flip the chops over to sear the other side for another 4 minutes. Transfer them to the oven and bake at 400 F degrees for 10 minutes.
2. You can substitute in unsalted butter for the ghee
3. You can make the caramelized onions and mushrooms up to 4-5 days in advance and store them covered in the fridge. I would make the pork tenderloin when you are ready to serve. Simply reheat the onions and mushrooms in a pan on the stove for about 5 minutes until warmed through.
4. Yes, you can freeze the caramelized onions and mushrooms in an airtight container in the freezer for up to 6 months. Thaw them in the refrigerator overnight and then reheat the onions and mushrooms in a pan on the stove for about 5 minutes until warmed through.