📖 Instructions

1. Prepare the Crust: Preheat your oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving an overhang on the longer sides to easily lift the bars out later. In a food processor, pulse the graham crackers until finely ground into crumbs. If you don't have a food processor, place crackers in a zip-top bag and crush them with a rolling pin until fine. Transfer crumbs to a medium bowl. Pour in the melted unsalted butter and granulated sugar, mixing until the crumbs are thoroughly moistened and resemble wet sand. Press this mixture evenly into the bottom of the prepared baking pan using the back of a spoon or your clean hands. Bake for 10-12 minutes, or until lightly golden. Remove from the oven and let cool completely on a wire rack while you prepare the filling.
2. Make the Blackberry Swirl: While the crust is cooling, combine the fresh or frozen blackberries, granulated sugar, and fresh lemon juice in a small saucepan. Cook over medium heat, stirring occasionally, for 8-10 minutes, or until the berries have broken down and the mixture has thickened slightly, resembling a loose jam. Mash the berries gently with a fork or potato masher to break them up further. Remove from heat and let cool for about 10-15 minutes. For a smoother swirl, you can press the mixture through a fine-mesh sieve to remove seeds, but I often leave them in for a more rustic texture.
3. Prepare the Cheesecake Filling: In a large mixing bowl, using an electric mixer (handheld or stand mixer with a paddle attachment), beat the softened cream cheese on medium speed until smooth and creamy, about 2-3 minutes. Make sure there are no lumps! Gradually add the granulated sugar, beating until just combined and smooth. Don't overmix. Beat in the eggs one at a time, mixing well after each addition until just incorporated. Scrape down the sides of the bowl as needed. Stir in the heavy cream, fresh lime juice, and lime zest. Mix on low speed until everything is just blended and the mixture is smooth. Again, be careful not to overmix, as too much air can cause cracks.
4. Assemble the Bars: Pour the lime cheesecake filling evenly over the cooled graham cracker crust in the baking pan. Dollop spoonfuls of the cooled blackberry swirl over the cheesecake filling. Using a butter knife or a skewer, gently swirl the blackberry mixture into the cheesecake filling to create a marbled effect. Don't overmix the swirl, or it will just blend in; you want distinct ribbons of purple.
5. Bake the Cheesecake Bars: Place the baking pan in the preheated oven. Bake for 35-45 minutes, or until the edges are set and lightly golden, and the center has a slight jiggle when gently shaken. Resist the urge to open the oven door too often! This helps prevent cracking.
6. Cool and Chill: Remove the pan from the oven and let the bars cool completely on a wire rack at room temperature. This can take about 1-2 hours. Once cooled to room temperature, cover the pan loosely with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, until thoroughly chilled and firm. Chilling is crucial for clean slices and a perfect cheesecake texture.
7. Slice and Serve: Once fully chilled, use the parchment paper overhangs to carefully lift the entire slab of cheesecake bars out of the pan and onto a cutting board. Use a sharp, warm knife (wipe it clean between cuts for the neatest slices) to cut the cheesecake into 18-24 bars, depending on your desired size. Garnish with additional fresh blackberries and lime zest, if desired. Serve cold and enjoy every zesty, sweet bite!