Preheat your oven to 350°F (175°C) and line a 12-cup muffin tin with cupcake liners.

In a large mixing bowl, whisk together the flour, cocoa powder, baking soda, and salt until well combined.

In a separate bowl, cream the softened butter and granulated sugar using an electric mixer until light and fluffy, about 3-4 minutes.

Add the eggs one at a time, beating well after each addition.

Dissolve 1 tablespoon of instant coffee granules in the buttermilk and stir until completely dissolved.

Gradually add the dry ingredients to the butter mixture, alternating with the coffee-buttermilk mixture. Begin and end with the dry ingredients, mixing on low speed until just combined.

Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full.

Bake in the preheated oven for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Remove from the oven and allow the cupcakes to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.

While the cupcakes cool, prepare the vanilla cream frosting by beating 1 cup of heavy cream with 1 ½ cups of powdered sugar and 1 teaspoon of vanilla extract until stiff peaks form.

For the chocolate coffee frosting, dissolve the remaining 1 tablespoon of instant coffee in 2 tablespoons of hot water and let it cool. Beat the remaining 1 cup of heavy cream with 1 ½ cups of powdered sugar, the cooled coffee mixture, and ¼ cup of cocoa powder until stiff peaks form.

Transfer the vanilla frosting to a piping bag fitted with a large star tip and set aside. Do the same with the chocolate coffee frosting.

To create the marbled swirl effect, hold both piping bags together in one hand with the tips side by side. Gently squeeze both bags simultaneously while piping in a circular motion on top of each cooled cupcake, starting from the outer edge and working toward the center.

Serve immediately or refrigerate until ready to serve.