Step-by-Step Instructions:

1. Step 1: Whip the Butter: Place the two sticks of softened unsalted butter in a large mixing bowl. Using an electric mixer on medium speed, beat the butter until it reaches a creamy consistency.
2. Step 2: Add the Powdered Sugar: Gradually add the 1 cup of powdered sugar to the whipped butter, mixing on low speed until it is fully incorporated.