Preheat your oven to 375℉ (190℃) and grease or oil a 9x13” casserole dish. Set aside.
Place asparagus in a microwave-safe dish with a quarter cup of water. Cover and steam it for about three minutes until tender. Drain and set it aside.
Melt 2 tablespoons of the butter over medium-high heat in a large skillet. Once melted, add the cubed chicken and cook it for 3 minutes until it browns. Flip the chicken pieces and continue cooking until they're cooked, for another 3 minutes. Avoid overlapping the chicken pieces in the skillet. If needed, do it in two batches, then add 1 tablespoon for each batch.
Once the chicken is done, transfer it to the greased casserole dish. Arrange the steamed asparagus on top of the chicken. Sprinkle with one cup of shredded cheddar cheese. Set aside.
In the same skillet, melt another tablespoon of butter, and add chopped onions, and sliced mushrooms. Sauté until tender, for 5 minutes at medium heat.
Add the chicken broth, heavy cream, salt, pepper, dried thyme, garlic powder, dried oregano, Dijon mustard, salt, black pepper, and sour cream. Whisk everything together and bring it to a simmer.
Keep stirring the mixture frequently as it simmers, allowing it to cook and thicken for approximately 10 minutes.
Once the sauce has thickened, pour it over the casserole in the dish. Sprinkle the remaining half cup of shredded cheddar cheese over the top of the casserole.
Bake the dish for about 20 minutes or until bubbly. Serve.
Notes
Storage: Store the cooked casserole in a sealed container or cover the casserole dish and refrigerate for up to 3 days. Reheat as needed in the microwave or oven until warm. Freeze the casserole in a sealed container for up to 3 weeks.*All Nutritional Data are Estimates Only Based on the Products I Used.*Yield: 6 servings, Serving Size: ⅙ of recipe, Net Carbs per Serving: 5g, Amounts per Serving-