Preheat oven to 350 degrees F (180 degrees C) or 320 degrees F fan-forced (160 degrees C fan-forced).
Grease and line 2 8-inch round cake pans.
In a measuring cup, whisk Egg (2) and Vanilla Extract (1 1/2 teaspoon). Set aside.
In a medium bowl, whisk All-Purpose Flour (225 gram), Baking Powder (1 teaspoon), Baking Soda (1 teaspoon) and Salt (1/4 teaspoon) together. Set aside.
In your mixing bowl, beat Unsalted Butter (190 gram) and Caster Sugar (250 gram) on high speed until light and fluffy.
Turn down to medium speed and drizzle in beaten egg mixture.
Throw in Unsweetened Cocoa Powder (55 gram). Mix until combined.
Turn your mixer down to low and drizzle in Buttermilk (330 milliliter).
Lastly, gradually add in your flour mixture.
Transfer into your 2 baking pans evenly. Drop the pan to release the air bubbles out.
Bake it in a preheated oven for about 30 to 35 minutes.
Let it cool in the pan.
Slice most of the Fresh Strawberry (500 gram). Keep some intact for the topping.
Remove the yellow bottom of the Chocolate Pocky (5 package) biscuits.
Make the chocolate buttercream: In your mixing bowl, add in Unsalted Butter (150 gram), Powdered Confectioners Sugar (150 gram), Salt (1/2 teaspoon), Instant Coffee (1/8 teaspoon), and Unsweetened Cocoa Powder (60 gram). Mix on low until it forms into a thick paste.
Add in your Dark Chocolate (100 gram), beat on medium-high for 3 minutes.
Add in Vanilla Extract (1 teaspoon), and continue beating. If it is too thick, add Milk (to taste), 1 tablespoon at a time to loosen it out. Beat for another 3 minutes on medium-high until smooth and fluffy.
Lay the first cake layer on your platter. Spread a layer of Chocolate Buttercream.
Place sliced strawberries on top.
Cover it with buttercream again.
Place the second layer on top.
Cover the whole cake with buttercream. (You don't need to be really even as you'll be covering it with Pocky and strawberries later)
Carefully layer chocolate Pocky biscuits on the side of the cake until the side is fully covered.
Strain Apricot Preserves (1 tablespoon) with some Water (1 tablespoon) to make a glaze. Set aside.
Top the cake with unsliced strawberries.
Brush strawberries with apricot glaze, then let it cool in the fridge.