To Bake Potatoes: Preheat oven to 350 degrees. Wash and dry each potato and pierce with a fork. Bake in oven for about 45 minutes- 1 hour until completely baked through. Remove from oven, wrap each in foil to keep warm. To cook in microwave: cook 1 potato at a time in the microwave. Cook for 3 minutes, turn over and continue to cook for about 3-4 minutes until soft. Remove from microwave, wrap each in foil to keep warm.
To Make Chicken à la King: In a large nonstick pan, melt butter over medium-high heat. Cook mushrooms, onions, red bell peppers in butter, stirring occasionally, until vegetables are soft about 4 minutes.
Stir in flour, salt, and pepper and stirring constantly, until blended; remove from heat. Using a whisk, stir in milk and broth. Continue to whisk until the flour becomes dissolved. Place back on medium-high heat and cook, whisking constantly until boiling. Continue to boil, stirring continuously for 1 more minute. Stir in chicken, pimentos and continue to cook until hot.
Cut baked potatoes in half. Mash each with a fork. Add about ¾ cup Chicken à la King to each.
This dish can be made ahead and reheated. It also freezes great.