In a medium bowl, combine graham cracker crumbs, melted unsalted butter, and brown sugar until well-mixed and crumbly. Press half into the bottom of a 9-inch round pan to form the crust.

In a large mixing bowl, beat cream cheese with an electric mixer until smooth. Gradually add lemon juice and sweetened condensed milk, mixing until fully incorporated.

Gently fold the fresh summer berries into the cream cheese mixture, ensuring even distribution.

Pour the berry filling over the prepared crust and smooth the top. Sprinkle the remaining graham cracker mixture on top.

Cover with plastic wrap and place in the freezer for at least 6 hours, or until firm.

Before serving, let sit at room temperature for 10-15 minutes for easier slicing.