In a large bowl, cream together the butter and granulated white sugar with an electric hand mixer on high speed until fluffy, about 2-3 minutes. (If using a stand mixer, use the paddle attachment.)
5 tbsp (70 g) unsalted butter, softened, 3/4 cup (150 g) granulated white sugar
Next add in the egg whites and vanilla and mix on medium-high speed for 1 to 2 minutes until pale and smooth.
2 egg whites, at room temperature, 2 tsp vanilla
Alternate adding the dry ingredients and the buttermilk to the butter mixture a little at a time until each has been added completely, mixing on low speed, then medium speed for each addition. Mix just until the batter is combined and smooth, scraping the sides of the bowl as necessary. The batter will be thick.
1/2 cup (120 ml) buttermilk, at room temperature
Divide the batter evenly among the 12 liners until each is two-thirds to three-quarters full.
Bake the cupcakes for 16 to 18 minutes or until a cake tester or toothpick comes out clean from the centers.Let the cupcakes cool in the pan for 10 minutes, then transfer them to a cooling rack to finish cooling.
For the White Chocolate Ganache
Make the white chocolate ganache by adding the chopped white chocolate, butter and heavy cream to a double boiler over a pot of boiling water.
4 oz (113 g) high quality white chocolate bar, chopped, 2 tbsp (28 g) unsalted butter, 3 tbsp (45 ml) heavy cream
Melt everything together, stirring occasionally.
Then remove the ganache from the heat and transfer to a small bowl.
Let the ganache cool to room temperature, then whip with an electric mixer on high speed until pale in color and fluffy. Transfer the ganache to a piping bag and cut a bit of the tip off.
For the White Chocolate Buttercream
Add the butter and salt to a large bowl. Whip with an electric mixer on high speed for 5 to 10 minutes until the butter is pale, fluffy and double in size.
3/4 cup (168 g) unsalted butter, softened, 1/8 tsp salt
Pour in the melted and slightly cooled white chocolate and combine on medium speed.
2 oz. (56 g) high quality white chocolate, melted and slightly cooled
Then sift the powdered sugar into the mixture ½ cup (65 g) at a time. Mix on low, then medium speed, making sure each addition is fully combined before adding the next. Scrape the sides of the bowl as necessary. When the last addition is incorporated, mix on high speed for about 1 minute until the frosting is light and fluffy.
1 1/2 cups (195 g) powdered sugar
Transfer the frosting to a piping bag fitted with a decorative tip.
Assembling the Cupcakes
Once the cupcakes are cool, remove the centers of each cupcake. Fill each with white chocolate ganache. Then pipe a generous amount of white chocolate buttercream onto each. Then serve!
Course: Dessert
Cuisine: American
Keyword: carrot cake cupcakes, white chocolate, white chocolate buttercream, white chocolate buttercream frosting, white chocolate cupcakes, white chocolate frosting