Beer Soup with Onions and Chicken Sausage

1/4 olive oil (more if needed)

3 large onions (sliced thin (6-8 cups) )

1 salt

freshly ground black pepper to taste

2 bottles dark lager

6 beef or rich chicken stock

2 bay leaves

1 allspice

1/2 dried thyme

croutons

1 link (chopped)