Start by whipping the cold heavy cream until it thickens slightly. Add sugar and fresh lemon juice, then continue whipping until soft peaks form. Gently fold in lemon zest to enhance the citrus aroma and flavor.
Spread a thin layer of whipped cream at the bottom of your dish. This helps hold the graham crackers in place. Arrange a full layer of crackers, breaking them if needed to fit evenly.
Spread one-third of the lemon cream over the crackers. Add a layer of fresh raspberries, slightly breaking larger ones. This ensures every bite has a burst of fruity flavor.
Continue layering crackers, cream, and raspberries two more times. Finish with a final layer of whipped cream on top. Decorate with extra raspberries for a beautiful presentation.
Cover the dish with plastic wrap and refrigerate for at least 4 hours. As it chills, the crackers absorb moisture and soften into a cake-like texture. Slice and serve once fully set.