
Melt the Butter: In a large pot, melt 8 tbsp of butter over medium-high heat until it begins to bubble.
Sauté the Vegetables: Add 8 oz sliced cremini or white button mushrooms to the melted butter and sauté for 2-3 minutes, or until the mushrooms are browned. Add 1 small chopped yellow onion and 1 diced green bell pepper, cooking until softened.
Add Garlic and Mustard: Lower the heat, then stir in 2 minced garlic cloves and ½ tsp dry mustard, allowing the garlic to become fragrant before proceeding.
Incorporate Flour: Sprinkle in ½ cup flour and cook for an additional 2 minutes, stirring to create a roux.
Gradually Add Chicken Broth: Slowly stir in 2 cups of low-sodium chicken broth, whisking continuously to avoid lumps. Bring the mixture to a simmer until it thickens.
Add Cream and Remaining Ingredients: Lower the heat and mix in 1 cup half and half, followed by 1 cup frozen peas, 7 oz diced pimentos (drained), and 3 cups cooked, diced or shredded chicken. Heat through until everything is warmed and combined.
Adjust Thickness (if needed): If the sauce appears too thick, staggeringly add additional chicken broth to reach your desired consistency.
Serve and Enjoy: Your Chicken a la King is ready to be enjoyed over rice, noodles, or flaky biscuits. Serve warm and enjoy!