Preheat oven to 350°F. Line cupcake pan with liners.
In a large mixing bowl, add eggs, oil, cocoa, water and vanilla extract. Combine well.
In a separate bowl, add flour, sugar, baking soda and salt. Combine well.
Add flour mixture to large mixing bowl of wet ingredients. Using a hand-held mixer, beat at medium speed until well combined.
Fill cupcake liners a little over 1/2 way. (If using a large ice cream scooper, fill each liner with one full scoop.)
Bake for 12-15 minutes or until a toothpick comes clean (a few crumbs is ok) when checking the middle of a cupcake.
Remove the cupcakes from oven and allow to cool on a cooling rack until close to room temperature (5-10 minutes.)
To frost cupcakes, beat butter on medium speed for 2-3 minutes until light and whipped. Add confectioner’s sugar, vanilla and heavy cream/milk.
Using a Wilton 2d Tip and a clear piping bag, frost cupcakes as desired.