Step 6: Simmer Until the Chicken Is Tender - Reduce the heat to maintain a gentle simmer and let everything cook for approximately 25 to 30 minutes. Stir the sauce occasionally and spoon some over the chicken to keep everything coated. The peppers should become tender, the mushrooms should soften, and the sauce should thicken slightly. Check the thickest part of the chicken with a
meat thermometer to make sure it has reached an internal temperature of 165°F. If the sauce becomes too thick, stir in a small splash of water.