Instructions

for the crust

Combine ice water and sour cream in bowl. Process flour, sugar, and salt in food processor until combined, about 5 seconds. Scatter butter over top and pulse until butter pieces are no larger than peas, about 10 pulses. Add ice water mixture and pulse until dough forms clumps and no dry flour remains, about 12 pulses, scraping down sides of bowl as needed.
Transfer dough to counter and knead briefly until it comes together. Form into 5-inch disk, pressing any cracked edges back together. Wrap in plastic wrap and refrigerate for 1 hour. (Wrapped dough can be refrigerated for up to 2 days or frozen for up to 1 month. If frozen, let dough thaw completely on counter before rolling.)
Adjust oven rack to middle position and heat oven to 350 degrees. Let chilled dough sit on counter to soften slightly, about 10 minutes, before rolling. Roll dough into 12-inch circle on lightly floured counter. Loosely roll dough around rolling pin and gently unroll it onto 9-inch pie plate, letting excess dough hang over edge. Ease dough into plate by gently lifting edge of dough with your hand while pressing into plate bottom with your other hand.
Trim overhang to ½ inch beyond lip of plate. Tuck overhang under itself; folded edge should be flush with edge of plate. Crimp dough evenly around edge of plate using your fingers. Push protruding crimped edge so it slightly overhangs edge of plate. Wrap dough‑lined plate loosely in plastic and freeze until dough is firm, about 15 minutes.
Place chilled pie shell on rimmed baking sheet. Line shell with double layer of parchment paper, covering edges to prevent burning, and fill with pie weights. Bake until edges are light golden brown, about 20 minutes. Remove parchment and weights; rotate plate; and bake until crust bottom dries out and turns light golden brown, about 20 minutes. If crust begins to puff, pierce gently with tip of paring knife. Set aside. (Crust needn’t cool completely before adding filling.)

for the filling

Meanwhile, cut tips from asparagus; set aside. Slice asparagus spears ½ inch thick. (You should have 1¾ cups ½-inch asparagus spear slices; reserve any extra for another use.) Melt butter in 12-inch nonstick skillet over medium heat. Add leek, ¼ teaspoon salt, and ¼ teaspoon pepper and cook until leek is softened, 3 to 5 minutes. Stir in sliced asparagus spears and cook until asparagus is bright green and crisp-tender, about 3 minutes. Set aside to cool slightly.
Whisk ¼ cup cream and cornstarch in large bowl until cornstarch dissolves. Whisk in eggs, lemon zest, garlic, remaining ½ teaspoon salt, remaining ½ teaspoon pepper, and remaining ½ cup cream until mixture is smooth.
Sprinkle ½ cup goat cheese evenly over crust followed by asparagus-leek mixture, spreading into even layer. Slowly pour custard evenly over top. Sprinkle remaining ½ cup goat cheese evenly over top. Arrange asparagus tips in single layer on top of custard. Press tips gently to submerge partially in custard. Sprinkle evenly with Parmesan.
Bake on baking sheet until top of quiche is lightly browned and center registers 170 degrees, 40 to 50 minutes, rotating sheet halfway through baking. Transfer to wire rack and let rest until cool to touch, about 2 hours. Slice and serve. (Quiche can be refrigerated for up to 3 days.)