BBQ Sweet Onion Rings

2 medium Sweet Onions
1/2 lb. melted butter
1/2 C. chili sauce
1/4 C. lightly packed brown sugar
3 T. Worcestershire sauce
1 T. grated Parmesan cheese
Dash of Tabasco sauce

Slice onions into thin rings and place in a casserole dish. Make a sauce by combining remaining ingredients. Simmer the sauce very slowly for 5 minutes. Pour sauce over onion rings and bake at 350°F until onion is tender, or about 30 minutes.
Stir occasionally while baking.