1n a 12 inch non stick frying pan, cook the onions with the oil over medium low heat until they are a deep golden brown. Stir often and keep an eye on the onions, it will take about 45 minutes to get the onions nice and caramelized.
2After the onions are nice and deep brown, transfer them to a pot with 4 cups of water, 1 sprig of thyme, and 1 can of beef broth. Bring to a boil then reduce heat and simmer for 30 minutes. Slice your French (or Freedom) bread in thick slices and toast the bread in a 450 degree oven until lightly toasted. Leave the oven on because you’ll be baking that soup in there soon enough.
3Get some oven proof bowls and place them on a baking sheet (this will make it easier to transfer the soup into and out of the oven) and fill the bowls ¾ full with the soup. Place your now toasted French (or Freedom) bread on top of the soup, pressing it slightly down into the liquid. Top with the shredded cheese. Bake the soup in the oven until the cheese is bubbling and starting to brown.