01 - In a bowl, mix flour, powdered sugar, and salt. Rub in cold cubed butter until mixture resembles coarse crumbs.
02 - Add egg yolk and 1 tablespoon cold water, stirring just until dough forms. Add more water if needed.
03 - Shape dough into a disc, wrap in plastic wrap, and refrigerate for 30 minutes.
04 - Preheat oven to 350°F. Roll dough on lightly floured surface to fit a 9-inch tart pan. Press dough into pan, trim excess, and prick base with fork.
05 - Line shell with parchment and fill with pie weights or dried beans. Bake 15 minutes, remove weights and parchment, then bake an additional 7 to 10 minutes until lightly golden. Cool completely.
06 - Heat heavy cream in a saucepan until just simmering. Pour over chopped chocolate; let sit 1 minute then stir until smooth. Stir in softened butter until glossy.
07 - Pour ganache into cooled tart shell and smooth the surface. Let set at room temperature for 10 minutes.
08 - Place fresh raspberries evenly over ganache. For shine, warm raspberry jam with water and brush gently over berries.
09 - Refrigerate tart for at least 30 minutes before slicing and serving.