For the crust:
Nonstick cooking spray
1 1/2 cups graham cracker crumbs
1 tablespoon sugar
4 tablespoons unsalted butter, melted
For the cheese filling:
16 ounces cream cheese, such as Philadelphia, at room temperature
¼ cup mascarpone cheese at room temperature
1 cup whole milk
1 cup sugar
1 1/2 cups whole-milk ricotta cheese (12 ounces)
1/2 cup Italian limoncello, at room temperature
1 teaspoon pure vanilla extract
4 large eggs, at room temperature
Preheat the oven to 350 degrees F. Position a rack in the center of the oven. Spray a 9 x13 x 2-inch baking pan with nonstick cooking spray.
For the crust, combine the graham cracker crumbs, sugar, and butter in a medium bowl and mix until moistened. Press the mixture evenly on the bottom of the prepared pan/ Bake for 10 minutes and set aside to cool.
For the filling, place the cream cheese mascarpone, and sugar in the bowl of an electric mixer fitted with the paddle attachment. Beat on medium speed for 5 minutes, until light and fluffy. Add the ricotta and beat for another minute, scraping down the bowl.
With the mixer on low, add the limoncello, vanilla, and milk and beat for one minute. With the mixer on medium-low, add the eggs, one at a time, until incorporated. Scrape down the bowl and mix until the batter is smooth. Pour over the crust.
Place the baking dish on a cookie sheet.
Bake for 60-70 minutes, until almost set in the center and lightly brown in spots on the top of the cake.
Cool to room temperature. Cover the dish with foil and refrigerate overnight. Cut into 16 pieces to serve.