French Onion Soup with Gouda

Ingredients

• 500g yellow onions, thinly sliced
• 2 tablespoons unsalted butter
• 2 tablespoons olive oil
• 2 garlic cloves, minced
• 1 teaspoon sugar
• 2 tablespoons all-purpose flour
• 4 cups beef broth (or chicken broth, or vegetable stock)
• 100g Gouda cheese
• 0.5 cup dry wine (optional)
• Baguette slices for topping
• Salt and pepper to taste