Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter on medium speed until soft and creamy.

NPR: Recipe: Devil's Food White-Out Cake

Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter and sugar together at medium speed for 3 minutes, until very smooth.

NPR: Holiday Sweets: On the Road (and in the Mail)