Objective: How to Make Classic Buttercream Frosting

Which of the following solutions is more sound in terms of naive physics reasoning?

Available choices: 1. To make Classic Buttercream frosting, put 1 cup of softened unsalted butter into a mixing bowl. Sift into the butter 4 cups of confectioners sugar. Beat with a hand mixer, add in 2 teaspoons vanilla extract and 2-3 tablespoons of powdered milk until frosting reaches desired consistency.; 2. To make Classic Buttercream frosting, put 1 cup of softened unsalted butter into a mixing bowl. Sift into the butter 4 cups of confectioners sugar. Beat with a hand mixer, add in 2 teaspoons vanilla extract and 2-3 tablespoons of milk until frosting reaches desired consistency.;
2.