In this recipe, store-bought puff pastry is topped with caramelized onions, salty pancetta, and creamy Brie. Perfect for brunch, lunch, or as an appetizer!
Heat oven to 350ºF. In a medium skillet on medium-low heat, melt 1 tablespoon of butter and add the sliced onion. Stir every 1 to 2 minutes until uniformly golden in color, about 25 minutes. Season with salt and pepper.
In a separate non-stick skillet over medium heat, cook the pancetta, stirring every 1 to 2 minutes, or until fat is rendered and pancetta is lightly browned, 8 to 10 minutes.
Carefully unfold puff pastry sheet onto a lightly floured surface. Roll dough to approximately 11-by-11-inches. Transfer dough to a parchment-lined baking sheet. Fold edge over ¾ inch to create a border. Dock then entire crust with a fork every 2 inches to allow steam to escape when baked.
Bake the crust until just golden, 20 to 25 minutes.
Slice brie into pieces.
Melt remaining 1 tablespoon butter in a small bowl and gently whisk in mustard.
Remove crust from oven. Using a pastry brush, glaze entire crust with the Dijon mixture. Layer caramelized onions and pancetta evenly over puff pastry. Add brie and return to oven for 3 to 5 minutes to melt cheese slightly.
Garnish with marjoram and cut into pieces to serve warm or room temperature.
Notes
Tips:
Line your baking sheet with parchment paper to ensure the tart doesn't get stuck to it.
You'll need to be very patient when caramelizing the onion. Resist the urge to crank up the heat to make the process go faster. It needs to cook low and slow to caramelize properly.
If you don't have any fresh marjoram, you can try using fresh thyme instead.