Cream Cheese Frosting

Do not use low-fat or nonfat cream cheese or the frosting will turn out too soupy to work with.

1A. FOOD PROCESSOR METHOD: Process cream cheese, butter, sour cream, vanilla, and salt in food processor until combined, about 5 seconds, scraping down bowl as needed. Add confectioners’ sugar and process until smooth, about 10 seconds.
1B. STAND MIXER METHOD: Using stand mixer fitted with whisk, mix cream cheese, butter, sour cream, vanilla, and salt at medium-high speed until well combined, about 30 seconds, scraping down bowl with rubber spatula as needed. Add confectioners’ sugar and mix until very fluffy, about 1 minute.

SPICED CARROT CAKE WITH VANILLA BEAN–CREAM CHEESE FROSTING
The Indian tea called chai inspired this variation.
For the cake, substitute 1⁄2 teaspoon pepper for nutmeg, increase cloves to 1⁄4 teaspoon, and add 1 tablespoon ground cardamom along with spices. For the frosting, halve and scrape seeds from 2 vanilla beans and add seeds to food processor along with vanilla extract.