Preheat oven to 350 degrees. Line a muffin tin with paper cupcake liners. Set aside.
In a large bowl, sift together dry ingredients. In another bowl, whisk together the oil, buttermilk and vanilla. Slowly whisk the wet ingredients into the dry ingredients just until mixed (over-mixing will create a tough cupcake!).
Spoon the batter into the prepared pan. Bake for 20-24 minutes or until a toothpick inserted into the center of a cupcake comes out clean. Allow to cool in the pan for 10 minutes before placing on a wire rack to cool completely. Frost with coffee buttercream frosting.
Make the frosting:
In a large bowl, beat together butter and one third of the sugar until thick and incorporated. In a small bowl, combine vanilla, hot water and espresso until the espresso powder is dissolved. Add the rest of the sugar and the espresso mixture to the butter mixture. Beat on medium speed until smooth and slightly fluffy. Spread on cooled cupcakes and top with sprinkles!