Preheat oven to 350 degrees Fahrenheit. Prep 15 standard 1/2-cup-size muffin cups with liners.
In a small bowl or mug, pour the boiling water over the espresso powder, stir, and let cool.
In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.
Add the Baileys to the water and espresso.
In a large bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the butter and the granulated sugar and brown sugar with a mixer on medium speed, until light yellow and fluffy, about three minutes.
Add the eggs one at a time, mixing well after each addition.
Add the flour in thirds, alternating with the espresso-Baileys mixture. Continue beating until well combined.
Fill the fifteen muffin cups about three-quarters full.
Bake for about 20 – 22 minutes, until a toothpick inserted into the center of the cupcakes comes out clean.
Remove from oven, let cool for about five minutes, then remove the cupcakes to wire racks to cool completely.
Make the frosting. In the bowl of a stand mixer fitted with the whisk attachment (or in a large bowl if you’re using a hand mixer), pour in the whipping cream (the colder the whipping cream and the bowl, the better for whipping). Beat at low speed until the whipping cream begins to thicken. Add the Baileys and the powdered sugar, then turn the mixer to high and beat until the whipping cream thickens enough to form semi-stiff peaks.
Spread the whipped cream onto the cupcakes with a knife, or you can spoon it into a pastry bag fitted with the tip of your choice or even a Ziploc bag with the corner snipped off, then squeeze the icing onto the cupcakes.
Sprinkle a bit of espresso powder on top of each cupcake.