01 - Pulse flour, powdered sugar, and salt in a food processor until combined. Add cold butter and pulse until mixture resembles coarse crumbs. Add egg yolk and 2 tablespoons cold water, pulsing until dough just comes together. Add additional water if needed. Form dough into a disk, wrap in plastic, and refrigerate for 30 minutes.
02 - Preheat oven to 350°F.
03 - Roll dough on lightly floured surface to fit 9-inch tart pan. Press dough into pan, trim excess, and prick base with fork. Line with parchment and fill with pie weights or dried beans.
04 - Bake for 15 minutes, remove weights and parchment, then bake 5 minutes more until lightly golden. Allow to cool completely.
05 - Place chopped chocolate in heatproof bowl. Heat heavy cream in saucepan until just simmering, then pour over chocolate. Let stand 2 minutes. Add butter, vanilla, and salt, then whisk until smooth and glossy.
06 - Pour ganache into cooled tart shell, smoothing top. Refrigerate for at least 1 hour until completely set.
07 - Arrange fresh raspberries decoratively over ganache. For glossy finish, gently warm raspberry jam and brush over berries.