In a large mixing bowl, whisk together the dry ingredients: all-purpose flour, granulated sugar, cocoa powder, baking powder, and salt. Ensure there are no lumps to create a smooth batter.

Next, incorporate the wet ingredients into the dry mixture. Add the eggs, vegetable oil, and hot coffee, mixing until fully combined and the batter is smooth and glossy.

Using a large cookie scoop, fill each cupcake liner in the muffin tin with the batter, making sure to fill them about two-thirds full.

Bake the cupcakes in a preheated oven at 350°F (175°C) for approximately 18 minutes. Check for doneness with a toothpick.

Allow the cupcakes to cool in the muffin tin for 5 minutes, then transfer them to a wire rack to cool completely.

In another bowl, beat the softened butter until creamy, gradually mix in cocoa powder and powdered sugar until smooth, then add the sour cream and hot water, blending well before incorporating the cooled dark chocolate.

Once the cupcakes are completely cool, pipe the Chocolate Cloud Frosting onto each cupcake in swirls or peaks, adding chocolate sprinkles if desired.