01 - Set oven to 350°F (175°C) and allow to fully preheat.
02 - In a mixing bowl, combine all-purpose flour, unsweetened cocoa powder, granulated sugar, and salt.
03 - Cut in the cold cubed butter with a pastry cutter or food processor until the mixture resembles coarse crumbs.
04 - Stir in egg yolk and 2 tablespoons of cold water. Mix just until dough begins to come together, adding additional water if necessary.
05 - Shape dough into a disk, wrap in plastic wrap, and refrigerate for 30 minutes to firm.
06 - On a lightly floured surface, roll out dough to fit a 9-inch tart pan. Press into pan, trim excess, and prick the base gently with a fork to prevent puffing.
07 - Line tart shell 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 set and crisp. Let cool completely in the pan.
08 - In a small saucepan, heat heavy cream over medium heat until just below boiling. Pour hot cream over finely chopped dark chocolate in a mixing bowl. Allow to stand for 1 minute, then add unsalted butter and stir until smooth and glossy.
09 - Pour prepared ganache into the cooled tart shell and spread evenly. Refrigerate for at least 1 hour to fully set the ganache.
10 - Arrange halved strawberries over the set ganache in a decorative pattern.
11 - If desired, gently warm apricot jam and brush over strawberries to impart a glossy finish.
12 - Cut tart into slices and serve chilled or at room temperature.