In a saucepan, melt butter. Then add cocoa and stir together until combined. Then add boiling water. Allow mixture to boil for 30 seconds.
Immediately add the cocoa mixture into the dry ingredients and mix until just barely combined. In a measuring cup add the buttermilk, eggs, vanilla, and baking soda. Mix well. Then add into the rest of the mixture and stir until completely incorporated.
Bake at 350 for 18 minutes or until a toothpick comes out clean.
For The Frosting
While the cake is baking, it's time to make the frosting. Melt butter in a saucepan. Add cocoa and stir to combine. Turn off the heat.
Add milk, vanilla and powdered sugar and stir until well blended.
While the cake is still warm, frost your cake. Wait until room temperature to serve. Enjoy as is or with a scoop of ice cream.
Notes
This is Resa Detwiler's go-to chocolate cake and it is a 10/10! Moist, delicious and super easy to make.