Caramelized Onion Upside Down Tarts
These Caramelized Onion Upside Down Tarts are an excellent blend of savory and sweet, with caramelized onions, gooey Swiss cheese, and a glimmer of balsamic glaze all lodged into a golden puff pastry. They’re super simple to throw together but taste like something you’d order at a fancy restaurant. The best part? They’re brief, and elegant, and have that ideal ratio of crisp pastry and rich, melty cheese. Whether you’re serving them as a party appetizer or treating yourself to a light meal, these tarts will always be a hit.
12 Servings
Ingredients
- 1 17-ounce package puff pastry, thawed
- 4 tbsp olive oil
- 2 tbsp balsamic glaze
- 1-2 medium sweet onions sliced into rounds
- 1 tsp garlic powder
- Salt and freshly ground black pepper to taste
- 12 slices of Swiss cheese
- 1/4 c shredded Parmesan cheese
- 1 egg white
Instructions
- Preheat your oven to 400°F and get two baking sheets ready by lining them with parchment paper.
- Cut your puff pastry into squares—I like to do 6 per sheet, but you can adjust based on the size you want. Set them aside for now.
- On each baking sheet, drizzle 6 small pools of olive oil (so 12 total), and then add a touch of balsamic glaze to each one.
- Place a slice of sweet onion right on top of each oil and balsamic pool. Season with a sprinkle of garlic powder, some salt, and freshly ground black pepper.
- Next, layer a slice of Swiss cheese on top of each onion, followed by a puff pastry square. Make sure to press the edges down a bit so the pastry fully covers the cheese.
- Brush the tops of the pastry with egg white for that beautiful golden finish when it bakes.
- Pop them in the oven for 12-15 minutes, or until they’re perfectly golden and crisp.
- Once done, let them sit for about 5 minutes before flipping them over. For an extra touch of flavor, you can drizzle more balsamic glaze over the top before serving. Enjoy!
Notes
If you want to make these tarts gluten-free, it’s totally doable! Just swap out the puff pastry for a gluten-free version, which you can find in most grocery stores now. Make sure to check that your balsamic glaze is gluten-free as well (most are, but it never hurts to double-check). Everything else in the recipe is naturally gluten-free, so you can still enjoy all the deliciousness without any worries!