01 - Preheat oven to 350°F. Line a 9x9-inch square baking pan with parchment paper, ensuring overhang for easy removal.
02 - In a mixing bowl, combine graham cracker crumbs, melted butter, sugar, optional cinnamon, and salt until the mixture resembles wet sand.
03 - Reserve 1/2 cup of the graham cracker mixture for the topping. Press the remaining mixture firmly into the bottom of the prepared pan. Bake for 8–10 minutes until lightly golden. Allow to cool completely.
04 - In a small saucepan, combine frozen berries, sugar, and lemon juice. Cook over medium heat for approximately 5 minutes, until berries release their juices and begin to break down. Stir in the cornstarch slurry and cook for an additional 1–2 minutes until thickened. Let cool to room temperature.
05 - In a large bowl, beat the softened cream cheese until smooth. Incorporate sugar, vanilla extract, lemon juice, and sour cream; beat until thoroughly combined.
06 - In a separate bowl, whip the cold heavy cream to stiff peaks. Gently fold the whipped cream into the cheesecake mixture until fully integrated.
07 - Spread the cheesecake filling evenly over the cooled graham cracker crust.
08 - Dollop the berry sauce over the cheesecake layer. Utilize a skewer or knife to gently swirl the berry sauce through the top layer.
09 - Evenly sprinkle the reserved graham cracker crumble mixture over the top.
10 - Freeze, uncovered, for a minimum of 4 hours, or until firm.
11 - Remove from freezer, allow to sit at room temperature for 10 minutes, then lift from the pan and cut into individual bars. Serve immediately while frozen.