In a large bowl, mix all the dry ingredients. In a separate medium bowl, whisk together all the wet ingredients, except the boiling water. That is last.
Combine the wet and dry ingredients and stir until they just combine but a few dry streaks remain. Lastly, stir into the batter the boiling water and mix until it is incorporated.
Divide the batter among a muffin tin lined with paper cupcake liners.
Bake at 350 for about 12-16 minutes, or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool in the muffin tin, set on a wire rack.
Irish Cream Buttercream
In a stand mixer with a paddle attachment, beat the softened butter until smooth and light. Scrape down the sides once or twice to ensure it is uniformly mixed. Add in the sifted powdered sugar one cup at a time, mixing until it is incorporated before adding more.
Add in the salt, and vanilla. With the mixer on medium-low, add in the Irish Cream and then turn up to medium to beat until it becomes light and fluffy. It will take at least 6 minutes to get enough air incorporated. If the mixture is still too thick, add in whipping cream one tablespoon at a time. One or two should be enough.
Pipe on top of cupcakes as desired!
Mix the ingredients together in a microwave safe bowl, for approximately 30 seconds. Stir until the chocolate is melted and the mixture is combined. Set aside to cool before use. It will thicken.
Pipe the cooled chocolate ganache into the middle of the cupcakes with a piping bag and a round frosting tip.