Step 1

Place 8 ounces cream cheese on the counter and let sit at room temperature until softened, about 45 minutes. Line an 8x8-inch, 2-inch high baking pan with 2 sheets of parchment paper, positioning them perpendicular to each other so that the parchment hangs about 2 inches over all 4 sides of the pan to form a sling.

Step 2

Melt 1 stick unsalted butter in a small microwave-safe bowl in 20-second bursts until mostly melted, 40 to 60 seconds total (it will melt completely as it sits). (Alternatively, melt the butter in a small saucepan over medium heat.) Set aside to cool slightly.

Step 3

Break 12 whole graham cracker sheets into rough pieces and place in a food processor fitted with a blade attachment. Add 2 tablespoons granulated sugar and 1/8 teaspoon of the kosher salt. Process until the crackers are the texture of sand, about 15 seconds. Add the butter and pulse until combined, 6 to 8 (1-second) pulses. (If using graham cracker crumbs, just stir 1 1/2 cups crumbs, the sugar, salt, and melted butter together in a medium bowl.)

Step 4

Transfer the mixture to the baking pan. Use the bottom of a measuring cup or your fingers to press the crumbs into an even layer, making sure to reach the edges and fill the corners. Refrigerate while you prepare the filling.

Step 5

Place 1 1/2 cups cold heavy cream and 1/4 cup of the powdered sugar in the bowl of a stand mixer (or large bowl if using an electric hand mixer). Beat with the whisk attachment on high speed until stiff peaks form, 1 to 3 minutes. Transfer to a medium bowl.

Step 6

Finely grate the zest of 1 of the medium lemons into the now-empty bowl (no need to wipe clean). Juice the zested lemon until you have 2 tablespoons and add to the bowl. Add the cream cheese, remaining 1/4 cup powdered sugar, 1 teaspoon lemon or vanilla extract, and remaining 1/4 teaspoon kosher salt. Beat with the whisk attachment on medium speed until light and very fluffy, scraping down the sides of the bowl with a flexible spatula halfway through, about 3 minutes total.

Step 7

Transfer 1 cup of the whipped cream to the cream cheese mixture and gently fold together with a flexible spatula until just combined. Dollop the cream cheese mixture into the baking dish and spread into an even layer. Spoon 1 can blueberry pie filling over the cream cheese mixture and spread into an even layer.

Step 8

Dollop the remaining whipped cream over the blueberry layer and spread into an even layer. Top with 1/2 cup fresh blueberries and gently press into the whipped cream. Cover and refrigerate for at least 4 hours or up to overnight.

Step 9

When ready to serve, finely grate the zest of the remaining lemon; save the zested lemon for another use. Grasping the excess parchment, transfer the blueberry delight slab to a cutting board. Cut into 12 pieces, wiping the knife between each cut for cleaner cuts. Sprinkle with the lemon zest.