Step 1

Let 1 1/2 pounds cream cheese sit at room temperature until softened.

Step 2

Line a 9x9-inch, 2-inch-high square 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 3

Melt 8 tablespoons unsalted butter in the microwave or on the stovetop.

Step 4

Roughly break up 16 full-sized graham crackers with your hands and place in a food processor fitted with the blade attachment. Add 2 tablespoons packed light brown sugar and 3/4 teaspoon kosher salt. Pulse until fine crumbs form, 10 to 15 (1-second) pulses. Drizzle in the butter and pulse until combined, 6 to 8 (1-second) pulses. The mixture should hold together in your hand when squeezed, resembling medium-coarse wet sand. (If using graham cracker crumbs, just stir 2 cups crumbs, the sugar, salt, and melted butter together in a medium bowl.)

Step 5

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. Freeze while you prepare the filling.

Step 6

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

Step 7

Place the cream cheese and remaining 1/4 cup granulated sugar in the now-empty stand mixer bowl (no need to clean; use a second large bowl if using an electric hand mixer). Beat with the whisk attachment on medium speed until fluffy and creamy, 4 to 5 minutes. Scrape down the sides and up the bottom of the bowl with a flexible spatula as needed.

Step 8

Add 1/2 cup powdered sugar, 1/2 cup sour cream, 1 teaspoon vanilla extract, and 1/4 teaspoon kosher salt. Beat on medium-high speed until combined and smooth, 2 to 3 minutes. Add the whipped cream and gently fold together by hand with the flexible spatula until combined and no streaks remain; do not overmix or it will deflate. Transfer half of the mixture back to the whipped cream bowl.

Step 9

Add 1/2 cup ube jam and 1 tablespoon ube extract to the stand mixer bowl. Beat with the whisk attachment on medium speed until evenly combined, 1 to 2 minutes.

Step 10

Set aside 1/2 cup of the white cream cheese mixture. Transfer the remaining white cream cheese mixture onto the crust and spread into an even layer. Dollop the ube mixture over the white cream cheese mixture and spread into an even layer.

Step 11

Gently tap the bottom pan against the counter a few times to remove any air bubbles. Using a small spoon, dollop the reserved 1/2 cup cream cheese mixture evenly over the top. Run a chopstick or small thin knife through the white dollops to make a swirl pattern in the ube mixture.

Step 12

Cover the pan tightly with plastic wrap or aluminum foil. Refrigerate until firm, at least 8 hours or preferably overnight. (The longer it is refrigerated, the firmer it will set. For an even firmer texture, freeze for 1 hour more after refrigerating before serving.)

Step 13

Grasping the excess parchment, lift the slab out of the pan and place on a cutting board. Cut into 16 squares with a long, thin knife, dipping it in hot water and drying the knife between each cut to get the cleanest-looking slices.