Whip the chilled heavy cream in a mixing bowl until soft peaks form, about 2-3 minutes, creating a light, airy texture with gentle folds.
Add sugar, lemon zest, vanilla extract, and liqueur (if using) to the whipped cream, then gently fold until combined, ensuring the mixture stays fluffy.
Spread a thin layer of syrup or juice on the sliced ladyfingers or sponge cake to soak them slightly, making them soft and flavorful.
Layer a portion of soaked ladyfingers in the bottom of your glass dish, pressing them gently to cover the surface evenly.
Top the ladyfingers with a generous handful of berries, arranging them evenly across the layer to showcase their vibrant colors.
Spoon a layer of whipped cream over the berries, smoothing it out with the back of a spoon to create a clean, even surface.
Repeat the layering process—soaked ladyfingers, berries, and whipped cream—until the dish is filled, finishing with a layer of whipped cream and berries on top.
Gently swirl the berries into the cream for a streaked, rustic look, and garnish with additional lemon zest or berries if desired.
Cover the dish with plastic wrap and refrigerate for at least 2 hours to allow flavors to meld and the layers to set.
Serve chilled, with a spoon digging into the layers to reveal the colorful streaks and soft textures, ready to enjoy.