3 eggs plus one egg yolk
1/4 cup sour cream
2 Tablespoons sugar
1 teaspoon vanilla
1 1/2 cups cooked rhubarb
Flaky Pastry (yields 2 tart shells)
12 oz all purpose flour
1 teaspoon salt
1 Tablespoon sugar
1/2 pound unsweetened butter
3 Tablespoons sour cream
1/4 cup ice water, plus additional as needed
For the tart shell
1. Cut butter into 1/2-inch dice and freeze for 10 minutes. Whisk sour cream into ice water and chill. Measure flour, salt, and sugar into food processor. Pulse until blended. Add cold butter to flour mixture and pulse until pea-sized bits of butter remain. Add half the sour cream mixture and blend. Add more sour cream mixture until dough forms a ball. Additional water may be necessary. Do not mix beyond the ball stage.
2. Divide dough into two equal halves. Press into 4-inch circles, lightly flour, and wrap in plastic wrap. Chill for at least an hour, but not more than 2 days or freeze.
3. Preheat oven to 375 degrees. Roll out dough to 15-inch circle. Tuck into removable bottom tart pan. Prick bottom and sides with fork. Line with foil and pie weights and bake 12 - 15 minutes or until floor of tart has begun to color. Remove from oven. Carefully peel off foil and weights and cool tart shell on rack.
For the filling
1. Preheat oven to 400 degrees. If chilled, bring rhubarb to room temperature. Add eggs, yolk, sour cream, sugar, salt, and vanilla into food processor and pulse until well blended.
2. Place warm tart shell on rimmed baking sheet. Spread rhubarb into tart shell. Add egg mixture to brim of crust. Place on lowest rack in oven and bake until filling has set and begun to brown in places. Serve warm or room temperature. Do not refrigerate (crust will become soggy).