INGREDIENTS
8 tbsp
unsalted butter
4
medium yellow onions, thinly sliced (about 4½ cups)
1 clove
garlic, minced
2 tbsp
all purpose flour
1 cup
dry white wine
2 qt
low sodium beef stock
1 1/2 tsp
Kosher salt
1/2
freshly grated pepper
1/4 cup
dry sherry
small slices of bread, such as French or baguette
freshly grated parmesan cheese
freshly grated Gruyere cheese