Preheat the oven to 325F. Line a 9x5 inch metal loaf pan with non-stick foil or line with regular foil and spray foil with cooking spray.

In a food processor, process the graham crackers to make about ½ cup of crumbs. Add the butter and sugar and process until mixed. Press mixture into bottom of loaf pan and bake for 10 minutes.

Reduce oven heat to 300F.

Clean out the food processor with some water. Add the cream cheese and sugar and process until smooth, stopping to scrape bowl if necessary. Add the lemon juice, lemon zest and vanilla and process to blend, then add the egg yolk and process. In a separate bowl, whip the egg white until stiff. Fold the cheesecake batter into the egg white (or vice versa) and then transfer it to the loaf pan.

Before serving, grasp foil and lift from the pan. Cut into two large squares and then cut diagonally to make triangles. If you want, you can trim the edges before doing this, but it’s not necessary.