How To Make Frosting Thicker. If you dont want all the sweetness you can use cornstarch alone. For chocolate frosting you can use cocoa powder to thicken in place of powdered sugar for a more intense chocolate flavor.
Make sure that your cream is super cold before whipping to make it rise. Add powdered sugar to the frosting by slowing stirring in 1 tbsp. If it is runny chill it thoroughly.
Make Royal Icing Thicker- To thicken royal icing simply add more powdered sugar.
To balance out the sweetness of the powdered sugar you can add meringue powder as it does not have its taste and can make the icing thicker. Make sure to mix the frosting well. You can also use meringue powder or heavy cream to make your frosting thicker. At a time until your frosting thickens.