Slice the onions into thin strips. Place a deep pot on the stove with the butter. Add a little olive oil to prevent the butter from burning. Once everything is hot, add the onions and stir them around.

Cook the onions on very low heat. Halfway through cooking, add the salt, black pepper, and thyme. Stir and cover the pot. If needed, add a little water to finish cooking. The onions should be well softened.

Once the onions are softened, add the white wine and cook until the alcohol evaporates. In a separate pot, heat the beef broth and when it boils, add the onions with their juices. Simmer on low heat for about 20 minutes.

Peel a garlic clove and rub it on the slices of bread. Toast the bread on both sides under the oven grill. Place the onion soup in oven-safe bowls, top with the slices of bread, and sprinkle grated cheese on top of the bread.

Broil in the oven until the cheese is slightly golden. I recommend watching the video for a better understanding of the instructions.