Meet your new favorite fall appetizer! These Caramelized Onion and Apple Puff Pastry Tarts are buttery, crisp, and bursting with flavor from sweet onion jam, tart apples, and melty Gruyère. Simple to make, impressive to serve, and absolutely irresistible warm from the oven.
Stir the onion jam with a splash of balsamic to balance the sweetness, and set aside.
On a parchment-lined baking sheet, add ¼ of a tsp of olive oil, then layer 6 apple slices, thyme, thin smear of onion jam, and Gruyère.
Lay the puff pastry over the filling and crimp the edges by gently pressing down along the sides with a fork. Then brush the tops with egg wash and add a sprinkle of flaky sea salt.
Bake for 20–25 minutes, or until golden and puffed. Allow the pastries to rest for 2-3 minutes, then flip onto serving dish.
Garnish with fresh thyme and serve warm.
Notes
If you want to add more or less filling to the pastries, you can. The dough just needs to cover the filling so you can adjust them to be any size you like!Most puff pastry sheets come in a pack of two. This recipe can be easily doubled to make 12 tarts!