Preheat oven to 375 degrees
Cook the rice according to package instructions. Or rinse the rice under colder water in a strainer. Then add the rice, 2 ¼ cups water, and a teaspoon of salt to a pot with a tightly fitting lid. Bring the water up to a soft boil, stir the rice, turn the heat down to the lowest setting, cover tightly, and cook on lowest heat for 20 minutes. After the 20 minutes, turn off the heat, but keep covered until you are ready to serve.
To a preheated sauce pot, add a drizzle of olive oil and the scallions and cook for a few minutes while stirring so they don't burn. Then add the lentils and stir to combine the flavors and mix with the oil.
Add the sauce to the pot and bring to a soft boil. Reduce heat, cover and simmer until the lentils are cooked and tender, and most of the liquid is absorbed, about 10-15 minutes.
For the cauliflower, spread the florets out on a sheet pan, drizzle or spray with olive oil, then season with salt and pepper. Rub the oil and seasoning all over the florets and then spread them out again. Roast them in the 375 oven for 25 minutes until golden brown and fork tender.
While the cauliflower is roasting, bring the cauliflower sauce up to a simmer in a small sauce pot.
Make the cornstarch slurry by adding the 2 tablespoons of corn starch to the ¼ cup cold water and mixing until it dissolves. Whisk it into the simmering sauce and then reduce the heat. Continue to whisk as the sauce thickens to ensure no clumps form, just a few minutes. Turn off the heat and then add the roasted cauliflower to the sauce folding it in to completely coat it with the thick sauce.
Serve by first putting the rice in the bowl, then spooning the lentils over the rice, and last the cauliflower. Garnish with the green onions and sesame seeds. Enjoy!