Cupcakes

1. Preheat oven to 325. Prepare muffin tins with paper liners or baking spray.
2. Whisk flour, baking powder and salt together and set aside. Cream butter and sugar on a high until pale, light, and fluffy (about 5 minutes).
3. Add eggs one at at time, mixing thoroughly before adding the next one.
4. Add lime zest and lime juice. Add vanilla.
5. Turn mixer to low. Add the dry ingredients in three batches, alternating with the buttermilk in two batches. Mix only until just incorporated.
6. Fill each muffin cup ~3/4 full. Bake for 25 minutes or until a skewer shows only moist crumbs attached, rotating the pans at the halfway point.
7. Allow cupcakes to cool completely in the pans before removing. While the cupcakes are still warm, brush the tops with tequila or tequila/orange mixture if desired.

Tequila-Lime Buttercream

1. To make the frosting, place the stand mixer bowl over a simmering pot of water (the bottom of the bowl should not touch the water). Whisk the sugar and egg whites until the sugar is dissolved and the mixture registers 160 degrees with a candy thermometer.
2. Place bowl on the stand mixer fitted with the whisk attachment and whisk on high speed until the mixture is cool and holds stiff, glossy peaks (approximately 10 minutes).
3. Change to the paddle attachment and beat in one tablespoon of butter at a time on medium. The mixture might appear curdled but keep beating, it will pull back together.
4. Add lime juice and 1 Tbsp tequila. Increase speed to high and beat until the frosting reincorporates and is smooth and fluffy. Beat in remaining tablespoon of tequila, if desired.
5. Frost the cooled cupcakes with the butter-cream as desired. If desired, garnish with lime zest, lime slices, short straws and fleur-de-sel (see description at the top of this post).