Step 1

Preheat oven to 350° F. Place cupcake liners in a cupcake tin and set aside.

Step 2

In a medium bowl, whisk together flour, baking powder, baking soda, salt, cocoa and espresso. Set aside.

Step 3

In a liquid measuring cup, stir together the milk and vanilla. Set aside.

Step 4

In the bowl of a stand mixer, beat butter at medium-high speed until smooth and shiny, about 30 seconds. Gradually add sugar until light and fluffy, 3 to 4 minutes. Add eggs one at a time, beating well after each addition. Scrape down sides when necessary.

Step 5

With the mixer on the lowest speed, pour in one-third of the flour mixture, followed by half of the milk mixture. Mix until the ingredients are almost combined (batter may look slightly curdled, it will mix away!) Repeat and end with the last third of the flour mixture. When the batter appears combined, turn off the mixer, scrape the sides of the bowl with a rubber spatula and turn on medium speed once more to beat about 15 seconds longer.

Step 6

Pour batter into the cupcake tin with liners, filling each until about three-quarters full. Bake for 16 to 18 minutes, or until a toothpick inserted in the center comes out with just a few crumbs. Let cool for 5 minutes in the tin and then transfer to a wire baking rack to cool completely. Keep the oven on.

Step 7

Heat treat the flour. Spread flour across a baking sheet and bake in the 350° F oven for 5 to 10 minutes to kill any harmful bacteria. Let the flour cool completely before adding it to the frosting.

Step 8

In a large mixing bowl, beat the butter (with a stand mixer or electric hand mixer) until fluffy, about 5 minutes.

Step 9

With the mixer on low speed, gradually add in the brown sugar and confectioner's sugar until completely incorporated. Add the flour and mix until combined.

Step 10

With the mixer on medium speed, add the vanilla and salt and beat for 1 minute, until fluffy. Add milk until desired consistency is reached.⁴

Step 11

Transfer to a frosting bag with desired tip and frost the cupcakes. Sprinkle with mini chocolate chips and serve. Store in an airtight container at room temperature.