To prevent sticking, the eggplant slices are roasted on wire racks set over baking sheets. Alternatively, they can be roasted directly on well-oiled baking sheets; after roasting, use a thin spatula to carefully remove the slices. Hard Italian Asiago is too mild for this recipe–use a domestic Asiago (available in supermarkets) that yields to pressure when pressed. The torta is best served warm or at room temperature. See below for make ahead instructions
3 medium eggplants (about 1 pound each), halved crosswise and cut lengthwise into 1/2-inch-thick slices, outer thin slices of skin from each half discarded
3 tablespoons olive oil , plus additional oil for brushing wire racks
1 medium head garlic , outer papery skins removed and top third of head cut off and discarded
Ground black pepper
2 medium red bell peppers (about 8 ounces each)
2 large tomatoes (ripe), about 8 ounces each, cored and cut into 1/4-inch-thick slices
4 medium zucchini (about 8 ounces each), cut on steep bias into 1/4-inch-thick slices
4 slices white sandwich bread (about 6 ounces), torn into quarters
3 tablespoons unsalted butter , melted, plus additional softened butter for greasing pan
2 ounces Asiago cheese , grated on fine holes of box grater (about 2/3 cup)
Custard and Garnish
3 large eggs
1/4 cup heavy cream
2 teaspoons minced fresh thyme leaves
2 tablespoons lemon juice , from 1 lemon
3 ounces Asiago cheese , grated on fine holes of box grater (about 1 cup)
2 tablespoons shredded fresh basil leaves
FOR THE VEGETABLES: Sprinkle both sides of eggplant slices with generous 1 tablespoon kosher salt; transfer salted eggplant to large colander set over bowl. Let stand until eggplant releases about 2 tablespoons liquid, about 30 minutes. Arrange eggplant slices in single layer on double layer paper towels; cover with another double layer paper towels. Firmly press each slice to flatten and remove as much liquid as possible.
While eggplant drains, adjust oven racks to upper-middle and lower-middle positions; heat oven to 450 degrees. Set 2 wire racks on 2 rimmed baking sheets; brush both racks with oil. Place garlic cut side up on sheet of aluminum foil and drizzle garlic with 1 1/2 teaspoons oil; wrap foil tightly around garlic and set aside.
Arrange salted and pressed eggplant slices on oiled racks; brush slices on both sides with 2 tablespoons oil and sprinkle with pepper.
Brush peppers with remaining 1 1/2 teaspoons oil and place 1 pepper on each baking sheet with eggplant. Place baking sheets in oven; place foil-wrapped garlic on lower oven rack alongside baking sheet. Roast vegetables until eggplant slices are soft, well browned, and collapsed, and peppers are blistered and beginning to brown, 30 to 35 minutes, rotating baking sheets and turning peppers over halfway through baking time. Transfer peppers to medium bowl, cover with plastic wrap, and set aside; allow eggplant to cool on wire racks. Continue to roast garlic until cloves are very soft and golden brown, 10 to 15 minutes longer. Set garlic aside to cool. Reduce oven temperature to 375 degrees.
While vegetables roast, arrange tomato slices on double layer paper towels; sprinkle with 1 teaspoon kosher salt. Let stand 30 minutes, then cover with another double layer paper towels; gently press tomatoes to remove moisture.
While vegetables roast and tomatoes stand, sprinkle both sides of zucchini slices with generous 1 tablespoon kosher salt; transfer salted zucchini slices to large colander set over bowl. Let zucchini stand until it releases about 1/3 cup liquid, about 30 minutes. Place triple layer paper towels on large, microwave-safe plate. Arrange a third of zucchini slices on paper towels; cover with another triple layer towels, pressing to remove moisture. Repeat, arranging remaining zucchini in two additional layers separated by triple layer paper towels, and placing triple layer paper towels on top of final zucchini layer. Place another heavy, microwave-safe plate on zucchini stack; press firmly to compress. Microwave stack on high power until steaming, about 10 minutes. Using potholders, carefully remove stack from microwave and let stand 5 minutes; remove top plate.
When peppers are cool, remove skins. Slit peppers pole to pole; discard stem and seeds. Unfurl peppers so they lie flat; cut each pepper lengthwise into 3 pieces.
FOR THE CRUST: Pulse torn bread in food processor until coarsely ground, about ten 1-second pulses. With machine running, pour butter through feed tube and process until combined, about 4 seconds. Add 2/3 cup Asiago and pulse to combine, about three 1-second pulses. Transfer mixture to bowl. Do not wash food processor.
Thoroughly grease 9-inch springform pan with softened butter. Measure out 1 cup bread-crumb mixture and sprinkle in bottom of springform pan; using flat bottom of measuring cup, press crumbs into even layer. Holding pan upright, press additional 1 1/4 cups bread-crumb mixture into sides of pan, forming thick, even layer that stops about 1/4 inch from top of pan, (see illustration below). Reserve leftover bread-crumb mixture.
FOR THE CUSTARD: Squeeze garlic head at root end to remove cloves from skins. In small bowl, mash cloves with fork and place in food processor; add eggs, cream, thyme, and lemon juice. Process until thoroughly combined, about 30 seconds.
TO ASSEMBLE AND BAKE: (See illustrations below.) Arrange single layer of eggplant on top of bread-crumb crust, tearing pieces as needed to cover entire bottom surface. Sprinkle evenly with 2 tablespoons cheese. Arrange single layer of zucchini and sprinkle with 2 tablespoons cheese. Repeat with another layer of eggplant and cheese. Layer in all red pepper pieces; sprinkle with 2 tablespoons cheese. Pour half of custard over vegetables; tilt pan and shake gently from side to side to distribute evenly over vegetables and down sides. Repeat layering of eggplant and zucchini, sprinkling each layer with 2 tablespoons cheese (about 4 more layers). Pour remaining custard over vegetables; tilt and gently shake pan to distribute. Arrange tomato slices around perimeter of pan, overlapping to fit, then fill in center with remaining slices. Press tomatoes gently with hands. Sprinkle torta with 3 tablespoons reserved bread-crumb mixture; discard any remaining bread crumbs.
Set torta on baking sheet and bake on lower-middle rack until tomatoes are dry, bread-crumb topping is lightly browned, center of torta looks firm and level (not soft or wet), and torta registers internal temperature of 175 degrees on instant-read thermometer, 75 to 90 minutes. Cool torta for 10 minutes on wire rack; run thin-bladed knife around inside of pan to loosen, then remove springform pan ring.
TO SERVE: Slide thin metal spatula between crust and pan bottom to loosen. Let stand 20 minutes longer (to serve warm) or cool to room temperature, sprinkle with basil, and cut into wedges.
TO MAKE AHEAD:The eggplant, garlic, and peppers can be roasted, cooled, wrapped in plastic, and refrigerated for up to 24 hours before assembly. Or the torta can be assembled, baked, cooled, removed from the springform pan, wrapped in plastic, and refrigerated overnight. Allow the torta to stand at room temperature for about 1 hour before serving
Serves 6 to 8 as a main dish; 8 to 10 as a side