Step 1

For the chocolate buttermilk cupcakes:

Step 2

Preheat the oven to 350 degrees (F). Line a 12-cup cupcake tin with cupcake liners and lightly spray the liners with non-stick spray. Set aside.

Step 3

Melt the oil, butter, and chocolate together in the microwave, heating in 30 second increments, stirring between increments each time. You can also melt the oil, butter, and chocolate over very low heat on the stove top, but I find the microwave to be much easier. Whisk mixture until completely smooth and set aside to cool.

Step 4

In a medium-sized bowl combine the flour, baking soda, baking powder, cocoa powder, and salt; stir together until thoroughly combined and set aside.

Step 5

In a large bowl whisk together the eggs, yolk, sugar and vanilla together, beat until smooth. Add the cooled oil/butter/chocolate mixture and whisk until smooth. Add half of the flour mixture, then half of the buttermilk. Repeat the process until everything is added, and be sure to mix until JUST combined - then quickly stir in the hot water. It's important not to over mix, here! Just stir until evenly combined. Fill each cupcake liner 3/4 of the way full with batter (You will have enough batter to make more than 12 cupcakes). Bake for 16-18 minutes, or until a toothpick inserted in the center comes out clean. Repeat with remaining batter. Cool cupcakes completely before frosting.

Step 6

For the chocolate buttermilk buttercream:

Step 7

Sift together the confectioners sugar and cocoa powder, whisking well to ensure it's bump and lump free!

Step 8

Using a handheld mixer OR a stand mixer fitted with the paddle attachment, beat the butter on medium-high speed until creamy; about 2 minutes. Reduce speed to low and slowly add the sifted sugar/cocoa powder, alternating with the buttermilk, then add the vanilla and salt. Once all of the ingredients have been added, beat on high speed until light and creamy and combined; beat for at least 1 minute on high.

Step 9

Frost cooled cupcakes and top with any decorations if desired.

Step 10

Cupcakes stay fresh at room temperature in an airtight container for up to 4 days.