Spinach & Feta Puff Pastry Tart

Ingredients

• 1 sheet all-butter puff pastry (about 9 ounces / 250 g), thawed in the refrigerator according to its package
• 1 teaspoon all-purpose flour, for rolling
• 1 tablespoon olive oil
• 1 small yellow onion (100 g), finely diced
• 2 garlic cloves, minced
• 10 ounces frozen chopped spinach (285 g), fully thawed
• 4 ounces feta (115 g), crumbled
• 1 large egg
• 1/4 teaspoon dried oregano
• 1/4 teaspoon ground black pepper
• 1/8 teaspoon fine salt, optional depending on the feta

Method

1. 01

   Heat a conventional oven to 400°F (200°C). Put a rimmed baking sheet in the oven to heat. Squeeze the thawed spinach firmly in a clean towel until very dry; removing the water is essential for a crisp base.

2. 02

   Heat the oil in a skillet over medium heat. Soften the onion for 5–6 minutes, then add the garlic for 30 seconds. Add the squeezed spinach and stir for 1 minute to separate it and evaporate remaining moisture. Spread on a plate and let cool until just lukewarm.

3. 03

   On lightly floured parchment, roll the cold pastry into a rectangle roughly 10 by 12 inches. With a small knife, score a border 3/4 inch from the edge without cutting all the way through. Prick the inner rectangle several times with a fork. If the pastry feels soft, refrigerate it for 10 minutes while the filling cools.

4. 04

   Beat the egg in a small bowl. Reserve 1 tablespoon for brushing the border. Mix the remaining egg with the cooled spinach, onion, most of the feta, oregano, and pepper. Taste the feta before deciding whether to add the optional salt; do not taste filling after adding raw egg. Spread inside the scored border in a thin even layer, scatter over the remaining feta, and brush the bare border lightly with reserved egg.

5. 05

   Carefully slide the tart, still on its parchment, onto the hot baking sheet. Bake for 25–30 minutes, until the border is well risen and deeply golden, the base is browned underneath, and the filling is set and reaches 160°F (71°C). Check the underside with a spatula; bake a few minutes longer if it is pale. Let rest for 10 minutes, then cut into 6 pieces. Serve as a light meal with a separate salad, or cut smaller for sharing.

6. 06

   The total time allows for the filling to cool while the pastry is prepared, plus the final rest; thawing the pastry and spinach is additional. Refrigerate leftovers within 2 hours for up to 3 days. Reheat on a baking sheet at 350°F (180°C) until crisp and the center reaches 165°F (74°C). A microwave warms it but softens the base.