In a bowl, combine flour, sugar, lemon zest and salt; cut in butter until crumbly. Combine eggs, water and lemon juice until smooth; drizzle over flour mixture. Toss with a fork until mixture is moist enough to shape into a ball (dough will be sticky). Divide in half; shape into balls and wrap in plastic. Refrigerate for at least 30 minutes. Remove from the refrigerator; let stand 15 minutes before rolling.
On a floured surface, roll the dough to 1/8-in. thickness. Cut into 3-in. circles. Ease into 2-in. tart pans, pressing pastry onto the bottom and sides of pan. Bake at 400° for 10 minutes. Cool.
Place three to four berries in each shell. In a bowl, combine sugar, flour and lemon zest. Stir in sour cream and egg yolk. Spoon 1 tablespoon of filling over berries. Place pans on a baking sheet. Bake at 350° for 15-20 minutes or until pastry is golden and filling is set. Cool in pans for 1 minute before removing to wire racks.