French Onion Soup Sticks

Bahan-bahan (6 porsi)

• 6 slices sandwich bread
• 6 slices swiss cheese, cut in half diagonally
• 6 slices provolone cheese, cut in half
• 1/2 stick unsalted butter, divided
• 1 teaspoon olive oil
• 2 large onions, sliced
• 1 can beef broth
• 2 tablespoons white wine (optional)
• ¼ teaspoon dried thyme
• salt and pepper, to taste