key lime cupcakes with white chocolate frosting

These are the best homemade cupcakes I've ever made, without question. You MUST try them. This cake may be my go-to cake from now on, adding and subtracting ingredients to get different flavors. They were perfectly fluffy but moist and had such a lovely flavor. The trick is not to over-bake them.

Key Lime Cupcakes with White Chocolate Frosting
{adapted from CuisineNie, adapted from Food Network}
Makes about 18
3/4 cup (1 1/2 sticks) unsalted butter, at room temperature
1 cup granulated sugar
2 eggs, at room temperature
1 tsp pure vanilla extract
1 1/2 tsp grated key (or regular) lime zest
1 1/2 Tbsp freshly squeezed key (or regular) lime juice
1 1/2 cups cake flour
1/2 tsp baking powder
1/4 tsp baking soda
1/4 tsp kosher salt
1/2 cup buttermilk

The Frosting:
5 ounces good quality white chocolate, chopped into small chucks
3/4 cup unsalted butter, room temperature
3 1/2 cups powdered sugar, sifted
Pinch salt
1/2 tsp pure vanilla extract
1 Tbsp lime juice (bottled or freshly squeezed)
1/4 cup sour cream
lime zest or candied lime peel for garnish

* Preheat oven to 325 degrees F.
In the bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar on high speed until light and fluffy, about 5 minutes. With the mixer on low speed, add the eggs, 1 at a time, scraping down the bowl after each addition. Add the vanilla extract, key lime zest and juice and mix well. In a separate bowl, sift together the flour, baking powder, baking soda, and salt. In 5 parts total, alternately add the dry ingredients and the buttermilk to the batter, beginning and ending with the dry. Mix until just combined. Line a muffin pan with paper liners and fill each liner almost to the top with batter. A spring loaded 1/4 cup ice cream scoop works great for this and ensures the cupcakes are all the same size. Bake for 20-25 minutes or until the tops begin to *barely* brown and a toothpick comes out clean. Remove cupcakes from oven and allow to cool in the pan for 10 minutes and then transfer cupcakes to a baking rack to cool completely.

FROSTING: In a small heat proof bowl set over a pot of simmering water, carefully and slowly melt the white chocolate. Remove from heat and let cool until just slightly warm. Meanwhile, in the bowl of an electric mixer fitted with the paddle attachment, beat the butter until light and fluffy. With the mixer on low, gradually add the powdered sugar until well combined. Add the salt, vanilla extract, key lime juice, and sour cream and mix until very smooth. Add the melted white chocolate and mix just until incorporated. Frost the cupcakes and garnish with a bit of grated lime zest or candied lime peel.