Combine the sugar, flour, cocoa powder, baking soda, baking powder, and salt into a bowl. Stir together with a whisk until evenly combined

Add the vanilla, eggs, buttermilk, and oil and stir until combined

Once combined, add the hot coffee. Stir quickly to ensure the hot coffee is evenly distributed. The batter will be very thin

Set aside to cool

Cut the softened butter in tablespoon pieces.

Add 2 inches of water into a saucepan that fits the bowl of a stand mixer on top without touching the water. After the water is simmering, add the sugar, egg whites, and salt. Whisk to combine and continue to simmer, ensuring the water does not touch the bowl. Keep heating the mixture until the sugar is dissolved (it will be about 120 degrees)

Place the bowl in the stand mixer and whisk on high speed until mixture is thick and glossy. It should hold very stiff peaks.

Reduce the speed of the mixer to medium and add the butter one tablespoon at a time until incorporated. Reduce the speed to low and add the cooled coffee. Then add the coffee grounds. Turn up the speed to medium until well incorporated. Set aside

When all components are ready, cut the 2 cake layers in half through the middle so there are 4 even piece

Spread the frosting evenly between the layers and serve