Restaurant-Style French Onion Soup

Ingredients (14)

• ✓ ½ cup butter
• + 8 onions, sliced add to pantry
• + 2 cloves garlic, crushed add to pantry
• + ½ teaspoon salt, or to taste add to pantry
• + ½ teaspoon ground black pepper, or to taste add to pantry
• + 1 teaspoon dried thyme add to pantry
• + 1 cup red wine add to pantry
• + 1 tablespoon sherry add to pantry
• ✓ 2 tablespoons all-purpose flour
• + 2 quarts beef broth add to pantry
• + 1 French baguette, cut into 1/2-inch thick slices add to pantry
• ✓ olive oil, or as needed
• + 6 slices Swiss cheese add to pantry
• + 6 slices provolone cheese add to pantry