Waffled French Onion Soup

Bahan-bahan (5 porsi)

• ½ stick unsalted butter, divided
• 1 teaspoon olive oil
• 2 large white onions, sliced
• 1 can beef broth
• 2 tablespoons white wine (optional)
• ¼ teaspoon dried thyme
• Kosher salt and freshly ground black pepper, to taste
• 2 teaspoons cornstarch, plus more if needed
• 2 tubes Pillsbury Crescent Recipe Creations Seamless Dough Sheet (or other puff pastry sheets)
• 8 ounces gruyere cheese, shredded
• Chopped chives, for topping