French Onion Soup

Ingredients:

80g butter
4 large brown onions, sliced crossways into rings
2 garlic cloves
2 tsp plain flour
1.5L (6 cups) beef stock
125ml (1/2 cup) dry red wine
1 bouquet garni
Salt & freshly ground black pepper
Bread to serve
55g (1 cup) finely shredded gruyere/cheddar cheese