1/2 stick unsalted butter
3 med. onions, thinly sliced
1 1/2 c. dark beer
2 c. beef stock or canned broth
2 c. chicken stock or canned broth
12 (1/2" thick) French bread baguette slices
6 thin slices Gruyere cheese
Freshly grated Parmesan cheese

Melt butter in heavy large pot over medium heat. Add onions and saute until deep golden brown, stirring occasionally. Add beer. Cover and cook 5 minutes. Add broth stocks and bring to a boil. Reduce heat and simmer uncovered 30 minutes, stirring occasionally. Season to taste with salt and pepper.

Preheat broiler. Ladle soup in broiler-proof soup crocks. Top with toasted bread and cheese slices. Broil and sprinkle with cheese.