Instructions

for the ricotta pie

Line rimmed baking sheet with triple layer of paper towels. Spread 4 cups ricotta on paper towels into even layer, then cover with second triple layer of paper towels. Place second rimmed baking sheet on top and weigh down with several heavy cans. Let ricotta sit for at least 30 minutes or up to 2 hours.
Meanwhile, adjust oven rack to middle position and heat oven to 325 degrees. Make foil sling for 13 by 9-inch baking pan by folding 2 long sheets of aluminum foil; first sheet should be 13 inches wide and second sheet should be 9 inches wide. Lay sheets of foil in pan perpendicular to each other, with extra foil hanging over edges of pan. Push foil into corners and up sides of pan, smoothing foil flush to pan. Spray with vegetable oil spray.

for the crust

Process 14 whole graham crackers, broken into pieces, and ½ cup shelled pistachios in food processor until finely ground, about 30 seconds. Add 2 tablespoons sugar and ¼ teaspoon table salt and pulse to combine. Add 6 tablespoons melted unsalted butter and pulse until combined, about 8 pulses. Transfer crumbs to prepared pan. Wipe out processor bowl and blade and set aside. Using bottom of dry measuring cup or flat spatula, press crumbs into even layer in bottom of pan. Bake until crust is fragrant and beginning to brown, 18 to 20 minutes. Transfer pan to wire rack and increase oven temperature to 400 degrees.
Discard top layer of paper towels, then transfer ricotta to now-empty processor bowl. Add 1¼ cups heavy cream, ¾ cup sugar, 4 large eggs, 2 teaspoons grated orange zest, 1 teaspoon vanilla, and ½ teaspoon salt and process until well combined and smooth, about 30 seconds, scraping down sides of processor bowl as needed. Pour mixture into pan over warm crust. Bake until center of bars registers 160 degrees, 20 to 25 minutes (center will still be jiggly). Let cool to room temperature on wire rack, about 1 hour. Transfer to refrigerator until chilled, at least 2 hours. (Bars can be refrigerated for up to 2 days.)

for the orange sauce

Whisk ¾ cup orange juice, ¼ cup (1¾ ounces) sugar, 2 teaspoons cornstarch, and ⅛ teaspoon salt together in small saucepan. Bring to simmer over medium-high heat, whisking to dissolve sugar. Reduce heat to medium-low and simmer until thickened slightly, about 3 minutes, whisking occasionally. Off heat, stir in ½ teaspoon cider vinegar. Set aside to cool completely, about 30 minutes. (Orange sauce can be refrigerated for up to 2 days; bring to room temperature before serving.)
Remove bars from refrigerator and let sit at room temperature for 30 minutes. Meanwhile, cut away peel and pith from 2 oranges. Holding fruit over bowl, use paring knife to slice between membranes to release segments. Cut orange segments into thirds.
Run knife around edge of pan to loosen bars then, using foil sling, lift bars from pan. Slide offset spatula between foil and bars to loosen then slide foil out from under bars; discard foil. Cut into 12 squares. Top individual squares with orange segment pieces and ¼ cup shelled pistachios, chopped, and drizzle with orange sauce. Serve.