Cream together butter and ½ cup of confectioner’s sugar at a time. After each cup of sugar has been added, add Nutella 1 tablespoon at a time, then add vanilla and then beat on high for about 20 seconds to lighten the frosting. Add half-and-half, one tablespoon at a time until the buttercream has reached a consistency where it will hold it’s shape. Add pinch of salt and whip on high for a final 20 seconds. Use immediately or cover and refrigerate up to three days. To use once refrigerated, slowly allow to reach room temperature and then beat on low speed until the buttercream is smooth before using.