1. Prepare the Graham Cracker Crust: In a medium bowl, combine the graham cracker crumbs and 1/4 cup of granulated sugar. Pour in the melted butter and stir until the crumbs are evenly moistened and resemble wet sand.

2. Layer the Crust: Divide the graham cracker mixture evenly among your 8 mason jars or dessert cups. Use the back of a spoon or a small tamper to gently press the crumbs down firmly into an even layer at the bottom of each jar.

3. Whip the Cream Cheese Mixture: In a large mixing bowl, beat the softened cream cheese with 1/2 cup of granulated sugar until light and fluffy. Add the lemon zest, fresh lemon juice, and vanilla extract, continuing to beat until everything is well combined and smooth. Scrape down the sides of the bowl as needed to ensure no lumps remain.

4. Whip the Heavy Cream: In a separate, clean bowl, whip the heavy cream until stiff peaks form. Be careful not to over-whip, or it will become grainy.

5. Combine and Fill: Gently fold the whipped cream into the cream cheese mixture until just combined. Spoon or pipe the cheesecake mixture evenly over the graham cracker crusts in each jar.

6. Add the Berries and Chill: Top each jar with a generous portion of the mixed berries. Cover the jars with lids or plastic wrap and refrigerate for at least 2 hours, or preferably longer, to allow the cheesecake to set and the flavors to fully develop.

7. Serve and Enjoy: Once chilled, your no-bake lemon berry cheesecake jars are ready to be served!