01 - Preheat oven to 350°F (175°C).
02 - In a mixing bowl, whisk together all-purpose flour, cocoa powder, granulated sugar, and a pinch of salt.
03 - Cut in the cold, cubed unsalted butter using a pastry cutter or food processor until the texture resembles coarse crumbs.
04 - Add the egg yolk and 2 tablespoons cold water. Mix until the dough just comes together, adding an additional tablespoon of water if necessary.
05 - Shape dough into a disk, wrap in plastic wrap, and refrigerate for 30 minutes.
06 - On a lightly floured surface, roll dough to fit a 9-inch tart pan. Gently press into the pan, trim excess, and prick the base with a fork.
07 - Line the crust with parchment paper and fill with baking weights or dried beans. Bake for 15 minutes.
08 - Remove weights and parchment, then continue baking the crust for 10 to 12 minutes until firm. Allow to cool completely in the pan.
09 - Heat heavy cream in a saucepan just below a boil. Pour hot cream over the finely chopped dark chocolate in a bowl; let stand 1 minute. Add unsalted butter, then stir gently until ganache is smooth and glossy.
10 - Pour the ganache into the cooled tart shell, smoothing the top. Refrigerate for at least 1 hour until set.
11 - Arrange halved strawberries evenly over the set chocolate ganache.
12 - If desired, gently warm apricot jam and brush over the strawberries to add a glossy finish.
13 - Slice with a sharp knife and serve chilled or at room temperature.