Leek and Gruyère Tart

Instructions

1. Prepare the leeks
   Thoroughly wash the leeks to remove any grit. Cut them in half lengthwise, then slice thinly into half-moons. Heat butter and olive oil in a large skillet over medium heat. Add leeks and cook slowly, stirring occasionally, for about 15-20 minutes until soft and caramelized. Add minced garlic and thyme in the last 2 minutes of cooking. Season with salt and pepper, then set aside to cool slightly.
2. Prepare the pastry
   Preheat oven to 375°F (190°C). Roll out the puff pastry on a lightly floured surface to fit a 9-inch (23cm) tart pan with a removable bottom. Press the pastry into the pan, trimming any excess. Prick the bottom with a fork and line with parchment paper. Fill with baking weights or dried beans and blind bake for 15 minutes. Remove the weights and parchment, then bake for an additional 5 minutes until the bottom is lightly golden.
3. Make the filling
   In a large bowl, whisk together eggs, heavy cream, milk, nutmeg, salt, and pepper until well combined. Stir in half of the grated Gruyère cheese.
4. Assemble the tart
   Spread the cooled leek mixture evenly over the partially baked pastry shell. Pour the egg and cream mixture over the leeks. Sprinkle the remaining Gruyère cheese on top.
5. Bake the tart
   Place the tart on a baking sheet and bake in the preheated oven for 25-30 minutes, or until the filling is set and the top is golden brown. The center should be just slightly wobbly when gently shaken.
6. Rest and serve
   Allow the tart to cool for 10-15 minutes before removing from the pan. Garnish with additional fresh thyme leaves. Serve warm or at room temperature with a simple green salad on the side.