Line an 8-inch square baking pan with plastic wrap, foil, or parchment paper, leaving some overhang.

In a bowl or bag, crush the graham crackers. Mix the crushed crackers with the melted butter. Press the mixture evenly into the bottom of the prepared pan. Use the bottom of a glass or another pan to flatten and compact the crust. Refrigerate while preparing the filling.

In a large bowl, whip the heavy cream until it just holds stiff peaks. Add the softened cream cheese, confectioners' sugar, vanilla extract, lemon juice, and lemon zest. Beat until smooth and well combined.

Spread the cream cheese mixture evenly over the chilled graham cracker crust. Return the pan to the refrigerator.

In a small saucepan, combine the blueberries and granulated sugar. Cook over medium heat, stirring occasionally, until the sugar dissolves and the blueberries begin to release their juices, about 5 minutes. Remove from heat and let cool to room temperature.

Once the blueberry mixture is cool, spoon it over the cheesecake layer. Smooth it out gently.

Refrigerate for at least 4 hours, or until the bars are set. Once set, use the overhang to lift the bars out of the pan. Cut into 12 bars and serve.