Caramelized Leek & Onion Tart
A lovely rustic tart with buttery pastry, sweet caramelized alliums and a delicate Dijon and crème fraîche filling. Equally at home alongside a holiday meal or a simple green salad for lunch.
Servings: 6
Ingredients
- 1 sheet all-butter puff pastry about 8–9 oz, thawed
- 2 large leeks white and light green parts, cleaned and thinly sliced
- 1 medium yellow onion thinly sliced
- 1 tbsp olive oil
- 1 tbsp butter
- ⅓ cup crème fraîche
- 1 tsp Dijon mustard
- 1 large egg
- ½ cup grated Gruyère
- 1 teaspoon fresh thyme leaves
- Salt and freshly ground black pepper
Instructions
- Preheat oven to 400°F. Line a baking sheet with parchment paper.
- Heat olive oil and butter in a large skillet. Add onion and leeks with a pinch of salt.
- Cook over medium-low heat for 18–22 minutes, stirring occasionally, until soft, sweet and lightly golden. Avoid rushing this step. Add a tablespoon of water if the vegetables begin sticking.
- In a small bowl, whisk crème fraîche, Dijon and egg. Season with pepper.
- Unfold pastry onto the prepared baking sheet. Lightly score a ¾-inch border around the edges, taking care not to cut all the way through.
- Spread the crème fraîche mixture over the center, keeping the border clear.
- Scatter the caramelized leeks and onions over the filling. Sprinkle with Gruyère and thyme.
- Bake for 25–30 minutes until the pastry is puffed and golden and the filling is set.
- Cool for 5–10 minutes before slicing.
Make ahead: Caramelize the leeks and onions a day ahead. Assemble and bake shortly before serving.
Notes
Calories 315 · Protein 9 g · Carbohydrates 25 g · Fat 20 g · Fiber 2 g
CLB's little tip: A small pinch of nutmeg in the crème fraîche mixture would be lovely.