In a large mixing bowl, beat the softened unsalted butter with an electric mixer on medium speed until creamy and smooth, about 2 minutes.
Gradually add the sifted powdered sugar, about 1/2 cup at a time, beating on low speed until fully incorporated to avoid a powdered sugar cloud.
Add the vanilla extract and 2 tablespoons of heavy cream. Beat on medium speed for 2-3 minutes until the frosting is light and fluffy.
If the frosting is too thick, add the remaining 1 tablespoon of heavy cream and beat again until you reach the desired consistency.
Gently fold in the mini semi-sweet chocolate chips using a spatula until evenly distributed throughout the frosting.
Use immediately to frost cupcakes, cakes, or spread on cookies. For best texture, keep refrigerated if not using right away and bring to room temperature before serving.