Golden French Onion Tart

Introduction
This French Onion Tart is a rich, savory dish inspired by the flavors of French onion soup. With caramelized onions, melty Gruyère cheese, and crisp, buttery puff pastry, it’s an elegant yet easy recipe perfect for a holiday appetizer, brunch, or light dinner.

Ingredients
1 sheet puff pastry, thawed
2 large Vidalia onions, thinly sliced
2 tablespoons unsalted butter
1/2 cup beef stock
1 teaspoon fresh thyme leaves (or 1/2 teaspoon dried thyme)
1/4 cup grated Gruyère or Swiss cheese
Salt and pepper to taste
1 egg, beaten (for egg wash)
How to Make