Preheat the oven to 400 F and bake the potatoes until done. Keep them warm. Saute the mushrooms, celery, onions, red pepper and garlic in butter in a large frying pan. Stir-fry for about 3 to 4 minutes. Stir in steak, sauté until tender. Add the broccoli and snow peas. Cook for another 3 minutes; add the remaining ingredients. Cook and stir until heated. Cut the baked potato into quarters, lengthwise. Spoon vegetables and meat over potatoes. Serves 4.