Onion soup: How to chop the onion and what kind of cheese to put in it?
When I make French Onion soup I slice my onions very thin. It also helps to use a small onion so the pieces aren't so wide.

For the cheese I use gruyere cheese. It should be grated.

In order for the cheese to cook properly you need to have some stale french bread. It should be toasted lightly on both sides and then sliced fairly thin. Then you place the bread on top of the soup and then the grated cheese on top of that. Next put the soup in the broiler so that it melts the cheese.