Using a food processor or mini-chopper, pulse the graham crackers until finely ground.
Using a medium bowl, combine the graham cracker crumbs, brown sugar, and melted butter; stir until fully combined.
Lightly butter or grease an 8”x8” baking pan. Line the pan with parchment paper, letting the paper overhang on 2 sides. Press the crust mixture evenly into the bottom of the pan. (Tip: A flat-bottomed glass helps pack the crust mixture down evenly.)
Bake crust at 350°F for 8 minutes. Remove from oven and let cool.
Preheat oven to 325°F.
Using a countertop mixer, add cream cheese, sour cream and sugar; beat until smooth. Add eggs and vanilla; beat on low speed until well combined.
Pour batter over the baked graham cracker crust.
Using a medium bowl, combine all ingredients for Blackberry Layer (blackberries, flour, sugar and lemon juice); toss until well combined. Spread this mixture evenly on top of the cheesecake batter.
Next, make the Crumble by combining sugars, cinnamon and salt; stir until well combined. Add the melted butter; stir until well combined. Add the flour; stir until well combined. Sprinkle crumble evenly on top of the blackberries.
Bake at 325°F for 55-60 minutes, or until cheesecake is set and crumble is light golden brown. Let cool at room temperature for 45 minutes and then refrigerate for several hours before slicing.
