This tart is elegant simplicity at its finest. Blanched asparagus sits atop a layer of creamy ricotta, and paper-thin slices of prosciutto are draped over it.
Preheat oven to 375 degrees. Roll out pate brisee on a lightly floured surface to a 10-by-15-inch rectangle. Press dough into bottom and up sides of a fluted 8-by-11-inch rectangular tart pan with a removable bottom. Trim excess dough flush with edges of pan using a sharp paring knife. Prick bottom all over with a fork. Refrigerate for 15 minutes.
Meanwhile, prepare an ice-water bath. Bring a large saucepan of salted water to a boil. Cook asparagus until tender, 3 to 4 minutes. Remove with tongs or drain in a colander, and immediately transfer to ice-water bath. Let stand for 1 minute to stop the cooking process. Drain. Slice each spear in half lengthwise.
Line dough with parchment, and fill with pie weights or dried beans. Bake until edges are just golden, about 25 minutes. Remove pie weights, and bake until tart shell is golden brown and cooked through, about 15 minutes.
Spread ricotta over tart shell while still warm. Season with salt and pepper. Top with asparagus, and drape prosciutto over top. Drizzle with oil. Serve immediately.