Line an 8x8-inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.

In a medium bowl, mix the graham cracker crumbs, melted butter, and granulated sugar until the mixture resembles wet sand.

Press the crust mixture firmly and evenly into the bottom of the prepared pan. Chill while preparing the filling.

In a large bowl, beat the softened cream cheese until smooth and creamy.

Add the powdered sugar and vanilla extract, then beat until fully combined and fluffy.

In a separate bowl, whip the heavy cream to stiff peaks.

Fold the whipped cream gently into the cream cheese mixture until no streaks remain.

Spread the cheesecake filling evenly over the chilled crust and smooth the top with a spatula.

Arrange the blueberries in the upper-left corner to form the flag's star field, then place the strawberry slices in rows across the remaining top surface to resemble stripes.

If desired, brush the strawberries lightly with warmed strawberry jam for a glossy finish.

Refrigerate for at least 4 hours, or until firmly set.

Lift the cheesecake bars out of the pan using the parchment overhang, cut into squares, and serve chilled.