Step 1 Heat the oven to 450 degrees and place a rack in the lowest part of the oven. With your fingers, butter the bottom and sides of a 10-inch springform pan. Use all the butter; you will have a fairly thick coating. Finely grind 7 1/2 graham crackers in a food processor, careful not to over-process to a paste. Pour the crumbs into the pan, shaking and turning the pan to coat all surfaces well (the remaining crumbs will form a thicker layer on the bottom of the pan).
Step 2 In the bowl of a stand mixer (or in a large bowl if using a hand mixer), combine the ricotta, sour cream, sugar, lemon peel, zests, rose water, orange blossom water and vanilla. On low speed, gradually combine all the ingredients. Switch to high speed and beat until thoroughly combined, scraping the sides of the bowl as you go.
Step 3Add both eggs and mix, first at low speed and then high speed, scraping down the sides of the bowl, just until the ingredients are combined. Be careful not to over-mix.
Step 4Using a large spoon, drop the batter into the pan, starting in the center and working your way out to the edges so that the crumbs do not get mixed into the batter. Smooth the batter to the edges of the pan, using the spoon to form an even layer.
Step 5Finely grind the remaining crackers, and spread the crumbs evenly over the top of the cake.
Step 6Center the cake pan on a baking sheet. Place the sheet in the oven and bake 8 to 10 minutes until the graham cracker topping is golden brown. Cover the top of the cake with foil and continue to bake until the cake has risen (including the center) about an inch over the sides of the pan, an additional 40 to 55 minutes depending on the oven. Rotate the cake after 20 minutes for even baking. Carefully remove the risen cake and cool (still on the cookie sheet) to room temperature; this will take a few hours.
Step 7Refrigerate the cake overnight before serving. Just before serving, dust the top of the cake with a light sprinkling of powdered sugar.