Drain ricotta overnight in a colander lined with paper towels, in the refrigerator.
Preheat oven to 325°F.
Mix graham crackers, almonds, and butter in a small bowl. Press into bottom of a greased 9-inch spring form pan. Bake for 10 minutes. Let cool.
Puree ricotta in food processor until smooth, about 30 seconds. Add egg yolks, sugar, zest, vanilla, salt, amaretto, and flour. Blend for 15 seconds and set aside in a large bowl.
In a small bowl, whip egg whites with a hand or stand mixer until stiff peaks form. Fold whites into ricotta mixture 1/3 at a time until just blended.
Spread mixture on top of cooled crust and bake in middle of oven until center of cake is just set/firm, about 1 hour to 1 hour, 10 minutes. Remove from oven.
Let cake rest for 15 minutes. Run a knife around edge of pan to release cake from sides. Refrigerate at least 4 hours or overnight before removing from pan. Garnish with fresh raspberries and lemon peel when serving.