When I use the extender recipe for chocolate cake I add cocoa..

When I use the extender for yellow I add vanilla...

What about spice cake.. so I don't lose my flavor???

Maybe add no additional flavoring - I've make it many times without adding flavoring (but not for a spice cake - only yellow or chocolate). I assume your using the extender for density and more batter (?).

Shhhhhh, don't tell my family as they always got a scratch carrot cake, but I didn't want to go to all the bother of shredding carrots ect so I bought a carrot cake mix, added the extra cup of flour, sugar, melted stick of butter and the cup of sour cream along with the 3 eggs and 1 1/2 cups of water (enhanced recipe). Oh, I also added drained pineapple because I like that in carrot cake, anyhow....everyone said that was the best carrot cake I have ever done, so very moist ect. it did not lose any flavor what-so-ever. So, I would maybe add a little cinnamon or allspice if you are concerned about flavor loss, but I bet the spice flavor will not be lost in the enhanced recipe. Good luck!

I add butterscotch pudding mix and it still tastes like spice cake and is very good!

I use the extender recipe for any & all flavors - usually w/o adding any extra flavoring.

I used the buttermilk spice cake recipe from the cake mix doctor book and it was great!