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