I was wondering if anyone has any suggestions. I have been trying to make Italian butter cookies and they keep coming out with a strange aftertaste. The recipe only calls for confectioners sugar, butter, vanilla, corn starch, salt and flour. The texture is perfect, but they have a strange aftertaste that I can't quite figure out. I even tried switching the vanilla extract for lemon extract to see if it was the vanilla, but they came out the same way. Any suggestions would be greatly appreciated.