Add 8 cups beef stock, 1 bay leaf, thyme and 1 tsp salt. Partially cover and simmer for 30 minutes for the flavors to meld. Add another 1/2 tsp salt and 1/2 tsp black pepper, or season to taste then remove from heat.
How to Make Crouton Topping:
While soup is finishing up, preheat oven to 400˚F. Slice baguette to 1/2” thick slices. Brush both sides lightly with olive oil, arrange on a baking sheet and bake for 6-8 minutes until golden brown at the edges.
Once the soup is ready to serve, top the toasts with half of the cheese and broil for 2-3 minutes until the cheese melts and turns golden in spots.
Pour soup into warm bowls and sprinkle remaining cheese over the hot soup. Top with hot cheesy toasts then serve.