First Step: Prep Ingredients Slice the mushrooms, finely chop the onion, mince the garlic, and measure out the chicken stock and cream. If using chicken breasts, slice them evenly or pound to uniform thickness for even cooking. Season the flour with salt and pepper.

Second Step: Sear the Chicken Heat 1 tablespoon each of butter and olive oil in a large skillet over medium-high heat. Dredge the chicken pieces in the seasoned flour, shaking off excess. Sear the chicken for about 4 minutes per side until golden but not fully cooked. Remove the chicken and set aside.

Third Step: Sauté Mushrooms and Aromatics Reduce heat to medium. Add remaining butter to the skillet and sauté mushrooms until browned and their moisture evaporates, about 4 to 5 minutes. Stir in garlic and thyme, cooking for another minute until fragrant.

Fourth Step: Deglaze and Simmer Pour in chicken stock or white wine, scraping the skillet bottom to release browned bits. Let the liquid reduce by about one-third over 5 to 8 minutes to concentrate flavors.

Fifth Step: Make the Creamy Sauce Stir in the heavy cream, Dijon mustard, and optional grated cheese, mixing thoroughly to create a creamy, smooth sauce. Adjust salt and pepper to taste.

Sixth Step: Finish Cooking Return the chicken to the skillet, spoon the creamy sauce over the pieces, and simmer for 10 to 12 minutes until the chicken reaches an internal temperature of 165°F and the sauce thickens to coat the back of a spoon.

Final Step: Serve Garnish with fresh herbs if desired. Serve the creamy chicken and mushroom skillet warm alongside rice, potatoes, steamed vegetables, or a simple salad for a wholesome and satisfying meal.