In a large mixing bowl, whisk together the flour, baking powder, and salt until thoroughly combined. Set aside.
Using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on high speed for about 1 minute until creamy and smooth. Add the granulated sugar and continue to beat on high for another 2 minutes, ensuring the mixture becomes light and fluffy. Scrape down the sides and bottom of the bowl as necessary to ensure even blending.
With the mixer on low speed, add the eggs one at a time, followed by the vanilla extract. Once incorporated, increase to medium-high speed and beat until the mixture is smooth and cohesive, pausing to scrape the bowl if needed.
Gradually add the dry ingredients to the wet, alternating with the milk. Continue mixing on low speed to avoid overworking the batter. Once combined, increase to high speed and beat in the lime zest and freshly squeezed lime juice until just incorporated, ensuring the batter remains light and airy.
Divide the batter evenly among the cupcake liners, filling each about halfway to two-thirds full to prevent overflow during baking. Bake for 18 to 20 minutes, or until a toothpick inserted in the center of a cupcake comes out clean. For mini cupcakes, adjust the baking time to 11–13 minutes while maintaining the same oven temperature.
While the cupcakes are still warm, brush them lightly with tequila for an added punch of flavor. Allow the cupcakes to cool completely on a wire rack before applying the frosting.