Preheat your oven to 180°C or 350°F. Grease and line your cake pans with parchment paper. This step helps the cake release easily after baking and keeps the layers neat and smooth.

In a large bowl, add flour, sugar, cocoa powder, baking soda, baking powder, and salt. Mix everything well using a whisk so all the dry ingredients combine evenly.

Add eggs, buttermilk, vegetable oil, and vanilla extract into the dry mixture. Mix slowly until smooth. The batter will begin to look thick and creamy as everything blends together.

Slowly pour hot coffee into the batter while mixing gently. The batter will become thin, which is normal. This step helps create a moist cake with deep chocolate flavor.

Divide the batter evenly into prepared cake pans. Place them into the oven and bake for about 30 to 35 minutes until a toothpick inserted in the center comes out clean.

Remove the cakes from the oven and let them cool in the pans for about 10 minutes. Then transfer them onto a cooling rack and allow them to cool completely before frosting.

In a saucepan, melt butter over low heat. Stir in cocoa powder until smooth. Remove from heat, then add powdered sugar, milk, and vanilla extract. Mix until creamy and spreadable.

Place one cake layer on a plate and spread frosting evenly on top. Add the second layer and cover the entire cake with frosting. Smooth the sides and top for a clean finish.