In a small saucepan, combine blueberries, sugar, cornstarch, and lemon juice over medium heat.

Cook stirring gently until the berries release their juices and the mixture thickens into a glossy, deep purple syrup. Leave some berries whole. Remove from heat and chill completely.

In a large bowl, cream the softened butter, brown sugar, and granulated sugar for two minutes until light and fluffy.

Beat in the egg and vanilla extract until fully incorporated.

In a separate bowl, whisk the flour, graham cracker crumbs, baking powder, and salt. Gently fold into the wet mixture until a thick dough forms.

Scoop 3-tablespoon balls of dough onto a parchment-lined baking sheet. Bake at 350°F (175°C) for 11-13 minutes until edges are light-golden. Cool on the pan for 10 minutes, then transfer to a wire rack to cool completely.

Beat the softened cream cheese and butter until perfectly smooth. Gradually mix in sifted powdered sugar and vanilla until fluffy and white. Transfer to a piping bag.

Pipe a thick swirl of frosting onto each cooled cookie. Use the back of a warm spoon to create a slight indentation in the center of the frosting.

Dollop the chilled, glossy blueberry filling into the indented well. Finish with a light dusting of finely crushed golden graham cracker crumbs.