Prepare Cookie Crust: Heat oven to 325°F (160°C). Butter and line an 8-inch square pan with parchment paper. In a food processor, add the graham crackers and process until fine crumbs form. Add the melted butter then cover and process until blended.

Press Graham cracker crumb mixture evenly into the bottom of the pan and chill in the fridge until needed.

Crumble Topping: Using the food processor again make the topping: Add brown sugar, flour, and cold butter to the processor bowl and blend until the mix resembles a crumble topping, just a few seconds. Set aside. (Bakers tips: I don't wash the bowl between these stages because it's such a similar crumb)

Cheesecake Layer: Wipe the food processor mostly clean with a paper towel then add the cream cheese, eggs, lemon zest, lemon juice, vanilla, and sugar. Process until smooth and creamy.

To Assemble: Remove the cookie crust from the fridge and pour the cheesecake filling over. Generously dot over the blueberries.

Lastly, scatter over the crumble topping.

Bake until the topping is lightly browned and the center is almost set, roughly 55-65 minutes. Cool 1 hour at room temperature then refrigerate for about 4 hours or until chilled. Cut into 9 bars and enjoy!