Gargonzola Sauce for Pasta

1/4 cup butter or margarine
1/2 medium onion, chopped finely
1/2 yellow or red bell pepper, chopped finely
1 tomato seeded, diced
1/2 cup fresh mushrooms, chopped coarse
8 ounces gargonzola cheese
8 ounces sour cream
8 ounces pasta (whatever kind you like)

Prepare pasta according to package directions and set aside. In a medium saucepan, saute the onions and peppers in the butter on medium heat until translucent. Don't let them brown. Add mushrooms and continue cooking until tender (2-3 min.). Turn heat to low and melt in the gargonzola stirring constantly. Once the cheese is completely melted, add the sour cream and just make it hot. Remove from heat and stir in the diced tomatoes. Serve over hot pasta.