Ingredients 1 sheet puff pastry, thawed in the refrigerator overnight 4 asparagus spears, hard ends removed and cut into 3-inch by 1/4-inch matchsticks 2 medium carrots, peeled and cut into 3-inch by 1/4-inch matchsticks 2 leeks, white and light green parts only, cut into 3-inch by 1/4-inch matchsticks 4 large eggs 1/2 cup plain Greek yogurt 2 tablespoons Dijon mustard 2 tablespoons whole grain mustard 1/4 teaspoon kosher salt 1/4 teaspoon black pepper Directions Place rack in center of oven and preheat oven to 400 degrees F. Line a large baking sheet with parchment paper or a silpat mat. Spray a 10-inch tart pan or shallow pie dish with non-stick cooking spray. On a lightly floured surface, roll the pastry into a 13-inch square. Fit pastry into the prepared dish, press into place and trim off any excess that flows over the top. (I like to do this by running a rolling pin right across the top of the pan). Line the pastry with foil, pressing the foil directly on the pastry's surface, then fill with pie weights or dry beans. Bake for 10 minutes, then remove from oven. Remove foil and weights. Let cool. Increase oven temperature to 425 degrees F. Place a steamer basket in a large saucepan, then fill the pan with water so that it nearly reaches but does not quite touch the steamer basket. Cover saucepan and bring to a boil, then drop in the cut asparagus, carrots, and leeks. Cover and let steam until the vegetables are easily pierced with a knife, about 5 minutes. Remove from saucepan, drain, and pat dry. In a medium bowl, whisk together the eggs, yogurt, Dijon mustard, whole grain mustard, salt and pepper. Set the prebaked pastry on the prepared baking sheet if it is not there already. Pour in the egg filling, then arrange the vegetables on top. Bake quiche for 20-25 minutes, until evenly puffed and lightly golden and a knife inserted in the center comes out clean. Transfer to a cooling rack and let rest 5 minutes before slicing. Serve warm or at room temperature.