In a medium saucepan, combine fresh blueberries with sugar and lemon juice over medium heat. Cook for about 5-7 minutes until the blueberries soften and release their juices.

In a small bowl, mix cornstarch with a tablespoon of water, then add to the saucepan, stirring until the mixture thickens, approximately 2-3 minutes.

Strain the sauce to remove skins and cool it completely.

Preheat your oven to 325°F (163°C) while preparing your cheesecake crust. Line a muffin pan with cupcake liners.

In a mixing bowl, combine graham cracker crumbs with sugar and melted butter until evenly moistened. Press this mixture firmly into the bottom of each cupcake liner.

Bake the crust for 5 minutes, then let it cool completely.

In a large mixing bowl, beat the cream cheese and granulated sugar until smooth and creamy, about 2-3 minutes.

Gradually add in the lemon juice, lemon zest, and vanilla extract, mixing well after each addition.

Incorporate the eggs, one at a time, ensuring each is fully blended before adding the next.

Carefully pour the cheesecake filling over the cooled crusts, filling each liner about three-quarters full.

Using a toothpick, gently swirl in the cooled blueberry topping for a marbled effect.

Bake for 17-20 minutes until the edges are set, but the centers have a slight jiggle.

Turn off the oven, and let the cheesecakes cool inside for a few minutes.

Transfer the muffin pan to a wire rack, allowing the cheesecakes to cool at room temperature for about 1 hour.

Refrigerate for at least 3-4 hours to set fully.