Finely chop the garlic and slice the onions into thin strips. If you have a food processor, this can speed up the process and save you from too many tears!

In a deep pot, heat the olive oil and butter over medium heat. Add the onions and garlic. Season with salt, stir, and cover the pot. Let it cook for about 7 minutes.

Uncover the pot, reduce the heat slightly, and let the onions cook for another 35 minutes, stirring occasionally.

After 35 minutes, add the brown sugar and stir well. Increase the heat to medium and caramelize the onions for 15 more minutes, stirring frequently.

Meanwhile, bring the water to a boil in a separate pot, then add the beef bouillon cubes and stir until dissolved.

Once the onions are caramelized, pour in the white wine and let it simmer for 5 minutes.

Add the prepared beef broth, bay leaf, thyme, and black pepper to the onions. Let the soup simmer for 30 minutes over medium heat.

Preheat your oven to 425°F (220°C). Slice the baguette into thin pieces and lay them on a baking sheet. Lightly brush each slice with olive oil on both sides.

Place the bread in the oven and bake for 5 minutes. Remove, flip the slices, sprinkle each with a little cheese, and bake for another 5 minutes.

Once the soup is ready, ladle it into bowls and sprinkle each serving with the remaining cheese, letting it melt into the hot soup. Top each bowl with 2 slices of toasted, cheesy baguette and serve immediately. Enjoy!