Stir together almonds, flour, sugar, salt, and ginger in a bowl. Add butter and, using two knives or your fingers, mix together until it resembles coarse meal. Add ice water, a little at a time until moist clumps of dough form. Gather dough into a ball and flatten into a disk. Wrap in plastic and chill for at least one hour or up to 1 day.
Preheat oven to 375. Roll dough onto a floured surface to a 12-inch round and transfer to a 9-inch diameter tart pan with a removable bottom. Fold dough overhang inwards, pressing to adhere and forming double-thick sides. Pierce dough with a fork and freeze for 20 minutes. Bake crust until light golden, about 30 minutes. Cool for 15 minutes.
While cooling, whisk lemon juice and sugar in a bowl. Add sour cream and then whisk in eggs until well blended. Pour mixture into crust. Bake tart until filling is set (about 35 minutes), covering crust edges with foil if they begin to brown too quickly. Cool tart completely on a rack and refrigerate at least 2 hours before slicing and serving.
Leah Koenig is a freelance writer whose work has been published in The New York Times Magazine, Gastronomica, Jewish Living, Lilith, Culinate, Beliefnet and other publications.