Prep. Preheat oven to 400 F and grease a 9" pie pan. Divide the asparagus (12 ounces) in half, leave half whole, and dice the other half into 1" strips.
Saute. Melt butter (1 tablespoon) in a large nonstick over medium heat. Saute the whole asparagus in butter until soft and slightly browned along the edges. Remove from pan, and set aside. Add the remaining butter (1 tablespoon) to the pan, along with the chopped asparagus, chopped leeks (1 1/2 cups), salt (1/2 teaspoon), and pepper ( 1/4 teaspoon). Saute until the leeks are translucent.
Combine + Assemble. In a large bowl, whisk the eggs (8 large), heavy cream (1 cup), and lemon zest (1/2 ) together. Stir in the cheese and slightly cooled sauted veggies. Pour the egg combo into the greased pie pan. Decorate the top with the whole asparagus.
Bake. Bake in the oven for 15 minutes, then remove from the oven, and twist the prosciutto (4 Ounces) into the quiche, making sure the edges curl down (this prevents them from burning). Toss back in the oven for 10 more minutes, allow the prosciutto to crisp. You'll know the quiche is done once the center is set. Allow quiche to cool before slicing, and enjoyyy a slice of this CHEESY goodness!