1. Preheat oven to 350.
2. Line (2) 12 count muffin tins with paper liners
3. Mix together flour, cocoa, baking powder, and baking soda, in a medium mixing bowl. Set aside.
4. Add butter to the bowl of a stand mixer (or large mixing bowl).
5. Add in sugars and beat until light and fluffy.
6. Add in eggs one at a time beating until well combined.
7. In a medium bowl mix together cocoa and boiling water until cocoa dissolves completely. Let cool. Add in buttermilk and vanilla. Mix well.
8. Turn mixture on low and add half the flour mixture and half of the buttermilk mixture. Repeat flour mixture and the buttermilk mixture. Mix until just combined.
9. Make sure to scrape sides and bottom of the bowl to ensure well combined.
10. Spoon batter evenly into lined muffin tins. **Fill no more than 2/3 full.
11. Bake for 15-18 minutes, or until a toothpick comes out clean.
13. Let cool completely before frosting.
Add all ingredients but the heavy cream to a mixing bowl. Mix on medium speed until all ingredients are incorporated and the frosting is smooth. Add in cream. Mix on high until light and creamy.