Line a 9-by-5-inch loaf pan with plastic wrap, allowing 4 inches of overhang. In a large bowl, using an electric mixer, beat the mascarpone with the heavy cream at medium speed until smooth and just firm; do not overbeat. Fold in the lemon curd and a pinch of salt.
Spread a 1/4-inch-thick layer of the lemon cream on the bottom of the pan. Arrange a single layer of graham crackers on top, breaking them to fit. Repeat the layering with the remaining lemon cream and crackers, finishing with a final layer of cream. Cover the cake with plastic wrap and refrigerate for at least 8 hours or overnight.
Uncover and invert the cheesecake onto a platter. Remove the plastic wrap. Serve with blueberries.
Note: The cheesecake can be refrigerated for up to 3 days.