Simple tart with figs and walnuts

Ingredients:

• 1 sheet (250g) frozen puff pastry, thawed
• 1 large egg, beaten
• 2 tsp olive oil + extra for greasing and drizzling
• Half a small onion, thinly sliced
• 1 tbsp. apple cider vinegar
• 55 g aged fontina, grated
• 8 dried figs, cut into crosswise slices
• 3 tbsp walnuts, coarsely chopped
• 0.5 cup crumbled feta
• 1 teaspoon fresh thyme leaves
• Coarsely ground black pepper
• Honey to drizzle
• Premium flour for working with dough
• Special equipment: pizza stone or baking sheet

Preparation:

1. Place a rack on the bottom shelf of the oven, place a pizza stone or baking sheet on it, and preheat to 200°C. Line another baking sheet with parchment paper.
2. Flour a work surface and roll out the puff pastry into a 25 x 37.5 cm rectangle. Transfer the dough to the prepared baking sheet. Use a knife to draw a border 1 cm from the edge and make small slits in the border (do not cut all the way through the dough). Prick the inside of the border with a fork (do not pierce the border).
3. Brush the dough with egg wash, transfer the baking sheet to a preheated baking stone, and bake until golden brown, 15-20 minutes. Let cool on the baking sheet for a few minutes. If the dough has puffed up in some spots, press it down with the bottom of a glass. Let cool completely on the baking sheet. The cooled cake can be wrapped and stored at room temperature for 1 day..
4. Meanwhile, heat the olive oil in a medium skillet over medium-low heat. Add the onion and a large pinch of salt and cook, stirring occasionally, until the onion is soft and deep golden, about 10 minutes. Add the vinegar and stir until completely absorbed. Remove the skillet from the heat and let the caramelized onions cool completely. It can be stored in the refrigerator for 1 day..
5. Sprinkle fontina all over the crust, forming a border. Top with caramelized onions, figs, and walnuts. Sprinkle the entire tart with feta cheese, thyme, salt, and pepper. Drizzle with olive oil.
6. Return the tart to the oven on the preheated baking sheet. Bake until the fontina cheese is melted, 10-15 minutes. Drizzle generously with honey and let cool for a few minutes. Cut into 16 squares and serve.