Chocolate Marshmallow Cupcakes

For Cupcakes: In a medium bowl, sift together cocoa powder, flour, baking soda, baking powder, and salt. In the bowl of a mixer, cream butter and sugars. Add eggs one at a time, mixing well between each. Mix in vanilla. Add dry ingredients in three parts. Scrape the sides of the bowl as necessary. Batter will be very thick. Add boiling water and mix on low until entirely combined. Fill cupcake liners 3/4 full and bake for 12-14 minutes or until a toothpick comes out clean. For Frosting: Combine egg whites, sugar, corn syrup, and vanilla extract in the bowl of a mixer. Bring 2 tbsp water to a boil. Place mixer bowl over boiling water. Using a hand mixer, mix on high until frosting forms and slightly cools. (approx. 5-7 minutes) Remove from heat and mix until completely cool. Pipe onto cupcakes using a Wilton 3M tip.