01 - Preheat the oven to 350°F.
02 - Combine all-purpose flour, unsweetened cocoa powder, granulated sugar, and salt in a mixing bowl.
03 - Add the cold, cubed butter and blend with a pastry cutter or fingertips until the mixture resembles coarse crumbs.
04 - Incorporate the egg yolk and 2 tablespoons cold water. Mix until the dough just comes together, adding an extra tablespoon of water if necessary.
05 - Shape the dough into a disk, wrap in plastic wrap, and chill for 30 minutes.
06 - Roll the chilled dough on a lightly floured surface to fit a 9-inch tart pan. Press evenly into the pan, trim the excess edges, and prick the base with a fork.
07 - Line the tart shell with parchment paper and fill with baking weights or dried beans. Bake for 15 minutes. Remove weights and paper, then bake for an additional 10 to 12 minutes until the crust is firm. Allow to cool completely.
08 - Heat the heavy cream in a saucepan until just below boiling. Pour over the chopped dark chocolate in a heatproof bowl. Let sit 1 minute, then add butter and stir until smooth and glossy.
09 - Pour the ganache into the cooled tart shell and smooth the top. Refrigerate for at least 1 hour until set.
10 - Neatly arrange the halved strawberries over the set ganache.
11 - If desired, gently warm the apricot jam and brush over the berries to add a glossy finish.
12 - Slice and serve chilled or at room temperature.