1. Cut dough into a 6-inch round piece (reserve remaining dough for another use), and press into a 9-inch round tart pan with removable bottom, making dough about 1/4 inch thick. Patch with pieces of dough if necessary. Refrigerate for 10 minutes. Trim dough flush with rim, and refrigerate for 30 minutes.

2. Preheat oven to 350 degrees. Line tart shell with parchment, and fill with pie weights or dried beans. Bake until edges are golden, about 20 minutes. Rotate tart shell, and remove parchment and weights. Cover edges with a strip of foil. Bake until bottom is crisp and lightly golden, 10 to 15 minutes more. Let cool on a wire rack for 10 minutes. Reduce the oven temperature to 325 degrees.

3. Pulse 1/3 cup hazelnuts in a food processor until finely ground. Stir together ground hazelnuts, flour, and salt.

4. Beat butter and granulated sugar until pale and creamy. Beat in egg. Add hazelnut mixture, and beat until just combined. (Frangipane can be refrigerated in an airtight container up to 1 week.)

5. Spoon frangipane into cooled tart shell, and smooth with a spatula. Let stand for 10 minutes. Bake until set, about 15 minutes. Let cool.

6. Prepare an ice-water bath. Bring a pan of water to a boil. Lightly score bottoms of apricots. Add apricots to boiling water, and blanch to loosen skins, about 1 minute. Using a slotted spoon, transfer to ice-water bath to stop the cooking, about 1 minute. Remove apricots, and gently peel. Cut in half, and remove pits.

7. Just before serving, beat cream with confectioners' sugar and vanilla until soft peaks form; whisk in creme fraiche. Spread over frangipane. Arrange 7 apricot halves, cut side down, around edge. Cut remaining apricot half into thirds and arrange in center.

8. Melt jam in a saucepan over medium-low heat. Stir in lemon juice, and set aside to cool for 5 or 10 minutes. Pour through a sieve; discard solids. Brush strained jam over apricots, and spoon remaining glaze over cream. Sprinkle remaining 2 tablespoons hazelnuts around apricots. Serve immediately.