Step 1 In the bowl of a stand mixer using the paddle attachment, or in a large bowl using a hand mixer, cream the softened butter. Add the cream cheese and beat, scraping the bowl once or twice, until fully incorporated but still a little stiff. Add the sugar and beat until somewhat fluffy and spreadable. Beat in the vanilla and lemon oil, careful not to overmix. This makes about 4½ cups frosting. You may not use all of the frosting for the cupcakes; the remaining will keep, covered and refrigerated, up to 1 week (soften at room temperature and beat again before using).