8 med. size Vidalia onions, peeled & sliced 1/4" thick, about 6 c.
2 tbsp. butter or as needed
1/2 c. heavy cream
1/4 c. dry cocktail sherry
1/8 tsp. pepper
1/2 c. grated Swiss cheese
1/4 c. grated Parmesan or Romano cheese

Preheat oven to 375 degrees. Saute half of onions in 2 tablespoons butter in large frying pan over low heat, stirring occasionally. Cook only until limp, 5-10 minutes; do not brown or discolor. Remove to 1 1/2 quart baking dish with slotted spoon; saute remaining onions, using more butter, if necessary. Add to onions in baking dish, along with cream, sherry and pepper. Stir to mix. Top with Swiss cheese and then Parmesan or Romano. Bake until top is a bit brown and all is bubbling hot, 15-20 minutes. Serves 6-8.