CREME FRAICHE FILLING: In the bowl of an electric mixer fitted with the paddle attachment, beat cream cheese and vanilla until soft.
In a separate bowl, whisk creme fraiche with a balloon whisk until it holds soft peaks.
Whisk 1/3 of the creme fraiche into cream cheese mixture to lighten. Fold remaining creme fraiche while gradually sifting the confectioners sugar over the top; fold just until combined. Cover with plastic wrap; place in refrigerator until ready to use, up to 2 hours.
DIRECTIONS FOR TART: On a lightly floured surface, roll out a disc of pate sucree 1/8-inch thick to a 3 3/4-inch x 13 1/4-inch fluted, rectangular tart pan with a removable bottom.
Brush off excess flour with a dry pastry brush. Carefullly transfer dough to tart pan, tuck dough into the edges, gently pressing along sides, and allow excess dough to overhang the edges. Trim the dough by running your rolling pin over the dough against the edges. Gently shape the edges by pressing the length of your forefinger against each flute along the sides.
Prick all over the bottom with the tines of a fork. Transfer to the refrigerator, and chill for 1 hour. Repeat with two more discs of dough. Reserve the remaining disc for another use.
Preheat oven to 375°F
Remove chilled tart shells from refrigerator, and line each with with a piece of parchment paper that overhangs the edges by at least 2 inches. Fill parchment with pie weights or dried beans.
Bake until just starting to color, about 20 minutes. Rmove parchment and weights from tart shells and return tart shells to oven. Continue baking until tart bottom is golden, abut 20 minutes more.
Transfer tart shells to a cooling rack, and allow to cool completely. Carefully remove tart shells from pans.
Using an offseet spatula, spread 1/3 of the creme fraiche filling into the bottom of each tart shell.
To glaze with blueberries, toss in a small bowl with 1/2 cup strained apricot jam. Arrange blueberries in one of the shells.
Arrange raspberries in second shell and brush carefully with remaining 1/2 cup apricot jam.
Arrange golden raspberries in the third shell. Generously dust with confectioners sugar.
Arrange tarts on a serving platter. Serve immediately.