English Onion Soup (English)

Originally uploaded by zannnielim
butter
Olive oil
Handful fresh sage leaves, 8 leaves reserved for garnish
6 cloves garlic, peeled and crushed
5 red onions, peeled and sliced
3 large white onions, peeled and sliced
3 banana shallots, peeled and sliced
11 ounces leeks, trimmed, washed and sliced
Sea salt and freshly ground black pepper
8 cups good-quality hot beef, chicken or vegetable stock
8 slices good-quality stale bread, 3/4-inch thick
7 ounces freshly grated Cheddar
Worcestershire sauce