This savory caramelized onion tart is a guaranteed crowd-pleaser, perfect for potlucks and parties. It’s made with a simple flour crust (or use your favorite store-bought gluten-free crust) filled with sweet and caramelized onions. Feel free to add feta cheese for an extra flavor boost, but it’s delicious on its own too!

Ingredients:

For the Crust:

• 1/3 cup unsalted butter, cold and cubed
• 1 cup all-purpose flour
• 1 pinch of salt
• 3 tablespoons ice cold water

For the Filling:

• 2 tablespoons unsalted butter
• 2 large red or yellow onions, thinly sliced
• 2 tablespoons balsamic vinegar
• 1 pinch of salt
• 3 sprigs fresh thyme, leaves picked
• 1/3 cup crumbled feta cheese (optional)
• Fresh basil (optional, for garnish)
• Balsamic reduction sauce (optional, for garnish)

Instructions:

1. Make the Crust: In a food processor, combine the flour, cubed butter, and salt. Pulse until the mixture resembles coarse crumbs. Slowly add the ice water while pulsing until the dough just comes together. Don’t overmix.
2. Transfer the dough to a lightly floured surface and shape into a disc. Wrap in plastic wrap and refrigerate for at least 30 minutes, or up to 1 hour.
3. Preheat oven to 350°F (175°C).
4. On a lightly floured surface, roll out the dough to a 1/4-inch thickness. Transfer the dough to a baking sheet lined with parchment paper. Prick the bottom of the dough with a fork a few times.
5. Bake the crust for 12 minutes, or until golden brown but still slightly soft. Remove from the oven and let cool slightly.
6. Caramelize the Onions: While the crust bakes, melt the butter in a saucepan over medium-low heat. Add the sliced onions and cook slowly for 35-40 minutes, stirring frequently, until the onions are softened and golden brown. Don’t rush this step, or the onions will burn.
7. Once caramelized, remove the onions from the heat and set aside to cool.
8. Assemble the Tart: Increase oven temperature to 350°F (175°C). Spread the caramelized onions over the cooled crust. If desired, fold the edges of the crust over the onions. Top with crumbled feta cheese (optional).
9. Bake for an additional 12-14 minutes, or until the filling is heated through and the crust is golden brown.
10. Let the tart cool slightly before serving. Garnish with fresh basil and a drizzle of balsamic reduction sauce (both optional).

Tips:

• Feel free to use a store-bought gluten-free pie crust if needed.
• The tart can be served warm or at room temperature.
• Leftovers can be stored in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven before serving.