Preheat your oven to 350°F. Lightly grease two 8-inch round cake pans, dust them with flour, and line their bases with parchment paper rounds.

Prepare 1 cup of hot coffee using either instant coffee granules or espresso powder in just-boiled water, then set it aside.

Sift the flour, cocoa powder, baking powder, and baking soda into a large bowl. Add both sugars and salt, then whisk thoroughly to combine and remove any brown sugar lumps.

In a separate medium bowl, whisk together the eggs, oil, sour cream, and vanilla. Pour this wet mixture into the dry ingredients, mixing with an electric mixer or whisk until just blended and thick, then gradually add the hot coffee in two stages, mixing until the thin batter is smooth.

Divide the batter evenly between the prepared pans and tap them on the countertop to release air bubbles. Bake for 30-33 minutes until a skewer inserted into the center comes out clean.

Transfer pans to a wire rack to cool for 15 minutes, then run a knife or offset spatula around the sides and invert the cakes onto the rack to cool completely.

While the cakes are cooling, prepare your chosen chocolate fudge frosting.

Once the cakes are fully cooled, place one layer on a serving plate and spread about ¾ cup of frosting over the top, extending to the edges. Carefully place the second cake layer on top, aligning it with the bottom layer.

Cover the entire cake with the remaining frosting, using an offset spatula to smooth the sides and create decorative swirls on the top layer, then enjoy!