This is the easiest, no-fail Roast Pork Gravy Recipe! The trick is my easy time-saving make-ahead gravy base. This gravy is thick, creamy, and full of flavor. It starts with simple seasoning on the pork, including garlic and thyme. When roasted, those flavors come out in the fantastic drippings. The gravy is made with these drippings for rich deep flavor. Mix the gravy base, stock, and pork drippings for a perfect gravy every time!
Make the gravy base. Add the butter and the flour to a small saucepan and whisk on low heat until combined. Slowly whisk in ½ cup of the stock/broth until smoothly combined. Then whisk in the milk. Remove from the heat and set aside. You can store the base in the fridge for up to 5 days.
In a small bowl, mix the salt, black pepper, garlic powder, and thyme. Rub the outside of the pork tenderloin with olive oil and then the seasoning mixture. To a dutch oven preheated on high heat, place the tenderloin in the pan to sear the bottom for 4 minutes, then using tongs, flip the tenderloin over to sear the other side for 2 minutes. Add ¼ cup water to the pot and then move the pork in the dutch oven into the oven, center rack and cook at 400 F degrees for 20 minutes or until the internal temperature reaches 145 F.
When the pork tenderloin is done cooking,transfer it to a plate or cutting board and let it rest for 10 minutes tented with aluminum foil to allow the juices to redistribute.
Place the dutch oven on the stove on low heat and add ½ cup of water to the pot and whisk to get all of those yummy pork bits up from the bottom while bring it up to a simmer. Whisk in ½ cup of the stock and the gravy base you made in advance. Whisk everything together until it start to look like a thick gravy. Add more stock if needed to thin out the gravy and achieve the consistency you want. Add a pinch of ground black pepper and taste for salt. If it needs salt, add a pinch.
Slice the pork and pour the gravy over top, serving the remaining on the side. Enjoy!