Caramelize the onions: In a large pot, heat the butter and olive oil, add the sliced onions, and sauté over medium heat for 20-25 minutes until golden brown.
Add garlic and spices: Add the minced garlic, bay leaf, and thyme, stir.
Thicken the soup: Add the flour, sauté for 1-2 minutes, then pour in the wine and let the alcohol evaporate.
Pour in the broth: Add the hot broth, bring to a boil, and cook for another 20 minutes over low heat.
Prepare the bread bowls: Cut off the top of the bread loaves, remove the crumb, leaving walls about 2 cm thick.
Bake the bread: Place the empty bread bowls in the oven at 180°C for 10 minutes until crispy.
Serve: Pour the soup into the bread bowls, sprinkle with grated cheese, and bake for another 5-7 minutes until a golden crust forms.