01 - Preheat oven to 350°F (175°C).
02 - In a large mixing bowl, blend together all-purpose flour, unsweetened cocoa powder, granulated sugar, and a pinch of salt.
03 - Add cold, cubed unsalted butter to the flour mixture and cut in using a pastry cutter or food processor until the texture resembles coarse crumbs.
04 - Incorporate the egg yolk and two tablespoons of cold water. Mix until the dough begins to form, adding an additional tablespoon of water if necessary.
05 - Shape dough into a disk, wrap in plastic wrap, and refrigerate for 30 minutes.
06 - Roll out the chilled dough on a lightly floured surface to fit a 9-inch tart pan. Press into the pan, trim any excess, 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, then remove weights and parchment. Continue baking for an additional 10 to 12 minutes, until the shell is set and firm. Allow to cool completely in the pan.
08 - Heat heavy cream in a saucepan until just below a boil. Place finely chopped dark chocolate in a bowl, pour the hot cream over, and let stand for 1 minute. Add unsalted butter, then stir gently until the ganache is smooth and glossy.
09 - Pour the prepared ganache into the cooled tart shell. Smooth the surface and refrigerate for at least 1 hour to allow the ganache to set.
10 - Neatly arrange the halved strawberries over the set ganache.
11 - If desired, gently warm apricot jam and brush over strawberries to create a glossy finish.
12 - Slice and serve chilled or at room temperature.