In a mixing bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix well until the crumbs are well coated.
Press the crust mixture firmly into the bottom of the 8x8 inch baking pan. Use the back of a measuring cup or your hands to pack it down evenly.
In a separate mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy.
Gradually add the powdered sugar, fresh lemon juice, lemon zest, and vanilla extract. Continue to mix until the mixture is smooth and well combined.
In another bowl, whip the heavy cream until stiff peaks form.
Gently fold the whipped cream into the cream cheese mixture until fully incorporated, being careful not to deflate the whipped cream.
Spread the lemon cheesecake filling evenly over the crust in the baking pan. Smooth the top with a spatula.
Cover the pan with plastic wrap and refrigerate for at least 4 hours or until the cheesecake is set.
Once set, remove the bars from the pan using the edges of the plastic wrap and cut them into 12 squares.
Serve chilled and enjoy your delicious no-bake lemon cheesecake bars!