Please choose the correct ending to complete the given sentence: Food and Entertaining: [header] How to make cookie dough frosting [title] Cream the butter and brown sugar with an electric mixer. [step] Beat until light and fluffy for about 2-3 minutes in a large bowl. [title] Add the vanilla, salt, and powdered sugar.

Ending1: [step] Beat again until the peaks disappear and a light sticky wax film develops on the surface. [title] Drop the icing mixture into a clean, resealable plastic bag or bowl. Ending2: [step] Beat again until the mixture resembles frosting. [title] Spoon the mixture onto the baking sheet. Ending3: [step] Mix or blend with a wooden spoon until light and fluffy, about 2-3 minutes. Beat in the eggs one at a time, once the butter is thick. Ending4: [step] Blend until the mixture begins to turn thick. [title] Slowly pour in the flour and add the milk.

Answer format: ending1/ending2/ending3/ending4