Asparagus and Fava Bean Tart with Herbed Ricotta

Place an inverted large rimmed baking sheet on middle oven rack, and preheat oven to 425°F. Do not remove baking sheet while oven preheats. Fill a large bowl with ice water; set aside. Bring a large saucepan of salted water to a boil over high. Add asparagus and fava beans; cook 1 minute. Drain in a colander. Place colander in bowl of ice water; set aside.

Lightly flour a large sheet of parchment paper. Roll out puff pastry on parchment paper into a 16-x 12-inch rectangle, dusting pastry with flour as needed to prevent sticking. Brush off excess flour from pastry. Using a pizza cutter, cut 1/2-inch-wide strips from perimeter of pastry; set strips aside. Lightly brush some of the beaten egg around pastry perimeter. Gently and loosely twist each pastry strip. Return pastry twists to pastry perimeter, placing on top of brushed egg and pressing gently into pastry base to seal. Trim any overhang from twists. Using a fork, prick the flat pastry surface 40 times; lightly brush with additional beaten egg. Slide parchment with pastry onto an 18-x 13-inch rimmed baking sheet. Using a paring knife, lightly score interior perimeter of pastry just inside twist border. Freeze 10 minutes.

Meanwhile, drain asparagus mixture, and pat dry; set aside. Stir together ricotta, 1/4 cup Parmesan, lemon zest, thyme, salt, pepper, and remaining beaten egg in a medium bowl; set aside.

Remove baking sheet with pastry from freezer, and place on top of preheated inverted baking sheet in oven. Bake until puffed and lightly browned, 12 to 15 minutes. Remove from oven. Reduce oven temperature to 375°F

Using a small offset spatula, gently spread ricotta mixture over puffed par-baked pastry, pressing gently to slightly flatten; sprinkle with remaining 1/2 cup Parmesan. Top evenly with asparagus and fava beans; drape with prosciutto slices. Immediately return to oven, and bake at 375°F until filling is set, about 10 minutes. Let cool 10 minutes. Garnish with mint, pepper, and Parmesan.