Ingredients

Instructions

  1. Preheat oven to 375 F with rack in middle.
  2. Arrange slices on a large baking sheet and bake in oven until golden, about 6-8 minutes. Let cool.
  3. Meanwhile, heat butter and oil in a 10-inch heavy skillet over medium heat until butter is melted, then cook onion, garlic, bay leaf, and thyme with 1/2 teaspoon salt and 1/4 teaspoon pepper, covered, stirring occasionally, 10 minutes.
  4. Uncover skillet and cook, stirring occasionally, until deep golden, about 10 to 15 minutes more. Add wine and cook until entirely evaporated, 1 to 2 minutes. Discard garlic clove, bay leaf, and thyme. Transfer to a small bowl and keep warm, covered.
  5. Preheat broiler.
  6. Arrange toasts on a large baking sheet, then top each with a rounded teaspoon of caramelized onions and sprinkle generously with shredded Gruyere. Broil 3- to 4-inches from heat until cheese is melted, 1 to 2 minutes (watch carefully).
  7. Steps that can be done ahead of time:
  8. Onions can be caramelized 3-5 days ahead and kept chilled.
  9. Bread slices can be toasted and cheese shredded 1-2 days ahead. Keep toasts in an airtight container at room temperature and keep cheese chilled.