Preheat oven to 350°F.
In a medium bowl whisk together flour, baking powder, and salt. Set aside.
Pour milk into a 1 cup measuring cup and add 2 tablespoons of freshly squeezed lime juice. Stir to incorporate and set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream together butter and sugar on medium-high speed until light and fluffy, about 2 minutes.
With the mixer on low, add in eggs one at a time, beating well after each.
Slowly add in the flour mixture in three batches, alternating with the milk mixture, starting and ending with the flour. Mix until just incorporated and make sure speed is always on low.
Divide batter evenly in a muffin pan. Bake for 18-24 minutes or until a toothpick inserted into the center comes out clean.
When done baking, remove cupcakes from oven and brush with tequila. After about 5 minutes, transfer cupcakes to a wire rack to completely cool before frosting.