When baking with Splenda, it's better to go half and half with sugar. It takes sugar for some of the chemical reactions to occur that makes baked good taste good. I never use the full amount of sugar while baking, even if I don't use Splenda. For instance, buttercream frosting has to have real sugar to stand up correctly. Using Splenda, even in small amounts turned the frosting into soup. Good tasting soup to dunk the cake into
