Beat butter on medium speed until smooth. Add the powdered sugar, Nutella, heavy cream, vanilla extract, and salt. Mix on low for 30 seconds until somewhat combined, and then turn mixer speed to medium high and beat for 2 minutes. Scrape down the sides of the bowl. If the frosting is too slack, add a ½ cup of powdered sugar to stiffen it up. If it’s too stiff, add a tablespoon of heavy cream and mix again.
Use frosting right away or store in an airtight container for up to 7 days or up to 3 months in the freezer. Thaw in the refrigerator and then beat for a few seconds. Add a splash of heavy cream if needed.
Notes
Makes enough to generously frost 12 cupcakes or lightly frost 24 cupcakes. Or a 3 layer 6 inch cake.