Cream cheese frosting
8 ounces cream cheese, softened but still cool
5 tablespoons unsalted butter, softened but still cool
1 tablespoon sour cream
½ teaspoon vanilla extract
1 ¼ cups (4 ½ ounces) confectioners' sugar
For the frosting: When the cake is cool, process the cream cheese, butter, sour cream, and vanilla in a clean food processor work bowl until combined, about 5 seconds, scraping down the bowl with a rubber spatula as needed. Add the confectioners' sugar and process until smooth, about 10 seconds.