Preheat your oven to 325°F (163°C) and line an 8x8 inch baking pan with parchment paper.

In a medium bowl, combine graham cracker crumbs, granulated sugar, and melted butter until resembling wet sand. Press into prepared pan.

Bake the crust for about 10 minutes, until slightly golden. Let cool.

In a large mixing bowl, beat softened cream cheese until creamy. Gradually add sugar and mix well.

Add eggs one at a time, mixing well after each addition. Then add vanilla, lemon zest, and lemon juice.

Fold in the fresh blueberries carefully.

Pour the cheesecake mixture over the cooled crust and sprinkle with streusel if using. Bake for 35-40 minutes.

Allow the bars to cool to room temperature, then transfer to the refrigerator and chill for at least 3 hours.

Lift out of the pan using the parchment, slice, and serve chilled.