01 - Preheat oven to 350°F.
02 - Combine all-purpose flour, unsweetened cocoa powder, granulated sugar, and a pinch of salt in a mixing bowl.
03 - Cut in the cold, cubed unsalted butter using a pastry cutter or food processor until the mixture forms coarse crumbs.
04 - Incorporate the egg yolk and 2 tablespoons cold water. Mix until the dough comes together, adding an extra tablespoon water if necessary.
05 - Shape dough into a disk, wrap in plastic wrap, and chill for 30 minutes.
06 - Roll dough on a lightly floured surface into a circle to fit a 9-inch tart pan. Press dough into the pan, trim any excess, and prick base with a fork.
07 - Line the crust with parchment paper and fill with baking weights or dried beans. Bake for 15 minutes. Remove weights and parchment, then bake an additional 10 to 12 minutes until firm. Allow to cool completely.
08 - Heat heavy cream in a saucepan until just below boiling. Pour over chopped dark chocolate in a bowl and let stand for 1 minute. Add butter, then stir until ganache is smooth and glossy.
09 - Pour chocolate ganache into the cooled tart shell and smooth the top. Chill in the refrigerator for at least 1 hour until set.
10 - Place strawberry halves over the set ganache in an even layer.
11 - Gently warm apricot jam and brush over the strawberries for a glossy finish, if desired.
12 - Cut into portions and serve chilled or at room temperature.