I saw this on the today show and adapted it a bit to my taste. original recipe asked for 1 cup of shredded gruyere cheese but i left that out b/c i don't care for it. i also just used a refrigerated pie crust and it all come out wonderful!
Preheat oven to 350 degrees with rack in lowest position. Cut off woody ends of asparagus then cut in small pieces on the diagonal. Cut the white and light green part of the leek in half, then thinly slice. In a large skillet, heat oil over medium heat. Add leek and asparagus and season with salt and pepper. Cook, stirring occasionally, until asparagus is crisp-tender, about 6-8 minutes. Let cool.
In a large bowl, whisk together the eggs, half-and-half, 1/2 tsp salt, 1/4 tsp pepper. Place piecrust on rimmed baking sheet. Top with asparagus mixture, then pour the egg mixture on top of that. Bake until center of quiche is just set, about 50-60 minutes, and rotate the sheet halfway through. Let stand 15 minutes before serving.
To store, let cool, then refrigerate up to one day. Reheat at 350 until warm, about 30 minutes.