Get Ready: Preheat your oven to 350°F (177°C). Line a 12-cup muffin pan with cupcake liners. This recipe makes about 15 cupcakes, so prepare a few extra liners or a second pan.
Mix Dry: In a large bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt until well combined. Set this bowl aside.
Combine Wet: In a separate medium bowl, gently whisk the vegetable oil, granulated sugar, egg, vanilla extract, and buttermilk until smooth.
Create Batter: Pour the wet ingredients into the dry mixture. Then, add the hot coffee or water and whisk everything until the batter is completely smooth. Don't worry if it seems a bit thin!
Bake Beautifully: Spoon or pour the batter into your prepared liners, filling each only about two-thirds full to prevent them from overflowing. Bake for 20-22 minutes, or until a toothpick inserted into the center of a cupcake comes out clean.
Cool Completely: Let the cupcakes cool in the muffin pan for 10 minutes, then transfer them to a wire rack to cool down entirely. For easier handling when filling, you can chill the fully cooled cupcakes in the refrigerator for 20-30 minutes.
Make the Glossy Ganache: While the cupcakes are cooling, place your finely chopped semi-sweet chocolate in a heatproof bowl. In a small saucepan, gently heat the heavy cream over medium heat until it just begins to simmer (avoid a rapid boil). Pour the hot cream over the chopped chocolate and let it sit undisturbed for 2-3 minutes to soften the chocolate. Slowly stir with a spoon or spatula until the chocolate is fully melted and the mixture is smooth and shiny. Transfer the ganache to the refrigerator to chill and thicken for at least 30 minutes.
Whip Strawberry Buttercream: As the ganache cools, make your filling. Grind the freeze-dried strawberries into a fine powder using a blender or food processor (this should yield about 1/4 cup of powder). In a large bowl, using a hand mixer or stand mixer, beat the softened butter on medium-high speed until it’s light and creamy (about 2 minutes). Gradually add the sifted confectioners’ sugar, strawberry powder, 2 tablespoons of heavy cream, and vanilla extract. Beat on low speed for 30 seconds, then switch to high speed and beat for another 2 minutes until the buttercream is light and fluffy. Taste and add an optional pinch of salt if you find it too sweet.
Fill the Surprise: Using a small, sharp knife, carefully cut a circular hole into the center of each cooled cupcake, about 1 inch deep. Remove the cone-shaped piece of cake. Spoon or pipe about 1-2 teaspoons of strawberry buttercream into this little pocket. Trim off the pointy end of the removed cake piece and gently press the round top back over the filling.
Top with Fudge: Spread a generous layer of your now-thickened chocolate ganache over the top of each filled cupcake. The ganache will set into a delicious, fudge-like topping.
Garnish & Serve: For a finishing touch, decorate with a fresh strawberry slice or some sprinkles, if desired. Serve these delightful cupcakes immediately or store them covered in the refrigerator for up to 5 days.