I want to make cupcakes tomorrow to surprise a friend who has been helping me through hard times. So I have my recipe for vanilla cupcakes which comes out at 15 syns per cupcake.. probably worth it for proper cupcakes but I'd like to bring the syns down a bit. I know I can substitute butter with lurpak lighter and my frosting will be philly light and quark which is fewer syns that butter cream but how do I know how to swap sugar for splenda in terms of quantities? It's supposed to be 2oz caster sugar in the cakes so how do I know what equivalent that is in splenda to get a good consistency and flavour? Any help much appreciated!