French Onion Soup

Another recipe from a swap.

6 Tbsp butter
1 Tbsp olive oil
3 lbs. medium yellow onions, peeled and thinly sliced
1 tsp sugar salt
1 Tbsp flour
8 cups beef stock
Freshly ground black pepper
4 hamburger buns
8 slices of provolone cheese

Over medium heat melt 3 Tbsp of the butter and the olive oil in a large heavy stock pot. Add sliced onions, cover and cook, stirring occasionally, until the onions are soft and translucent. Increase heat to high, rmove lid, add sugar and salt. Saute, stirring often until onions are very soft, and a deep golden brown. Reduce heat to medium, sprinkle in flour, and cook stirring constantly for 2 to 3 minutes. Add about 2 cups of stock and stir to blend and then add the remaining beef stock. Season to taste with salt and pepper, simmer for 30 minutes. Preheat oven to 425 degrees. Brush hamburger buns with remaining butter and place bread in oven and let this brown. When the bread has browned, remove it from teh oven. Gather 8 small oven proof bowls and spoon in soup, add on bun half, and then fill bowl with soup. Add one slice of provolone and place soup bowls in a baking dish and place in oven. When the cheese has toasted remove.