I am making an icing for eclairs and normally use icing sugar, melted chocolate, and corn syrup and refrigerate it overnight. I don't want to buy corn syrup for a couple of Tablespoons. What can I use instead ?
Making your own sugar syrup should work.
Corn syrup can be replaced by a sugar syrup. Combine one cup of pure cane sugar with 1/4 cup of water and heat over a low flame. Cool and use directly in a recipe. If preferred, cover the pan for three minutes to help remove sugar crystals, then add 1/4 teaspoon of lemon juice or cream of tartar to the pan and stir frequently until it reaches the soft ball stage (a drop of the syrup will form a ball when immersed in cold water). Cool and store in a sealed container at room temperature. It should keep for up to two months.
Alternatively, add granulated or brown sugar to a recipe that calls for corn syrup, cup for cup, then increase the amount of liquids used in the recipe by 1/4 of the amount of sugar added.
For your use, you'll probably want the liquid version.
I make a version of the eclair icing that doesn't involve corn syrup at all. I use cocoa powder,chocolate chips/coins (semi sweet),butter,water,icing sugar,and heavy cream. This version of a ganache topping results in a very stable topping for many desserts. It can be reheated with none too much fuss.