Sticky Fingers' Sweets vs Chloe's Kitchen sponge
I recently bought both the Sticky Fingers' Sweets and Chloe's Kitchen books (basically because I'd seen both authors on Cupcake Wars via YouTube). I decided to have a go at making mini cakes, so I baked the Sticky Fingers' Sweets basic vanilla cake, following the recipe exactly, and cut out rounds. The sponge tasted good and was relatively tender, if firm, but it hardly rose at all and looked quite anaemic so I tried the birthday cake recipe from Chloe's Kitchen and the sponge rose beautifully, had a good colour/texture but was quite sticky/greasy on the outside. I've attached a (bad) photo to show the results I got from the two sponges.
In the UK the only vegan margarine we have is spreadable tub stuff (Vitalite, Pure) and Stork, which is hard like butter. We don't get Earth Balance, but what I've been told before is that hard margarine should be used for baking, so I used Stork. When American recipes call for vegan margarine/Earth Balance, is that what they mean? Any other idea as to why the Sticky Fingers cake came out looking like that? If I reduce the oil content in Chloe's cake, will it have an adverse effect?
I use Earth Balance sticks for baking, which are hard like the butter/margarine I used in my pre-vegan days. So yes, it's probably best to use a hard vegan margarine when a recipe calls for Earth Balance. If it's not a baking recipe (ex. pan-frying something), I often use the spreadable tub Earth Balance.
For the Sticky Fingers recipe, did you measure out the flour by weight or in measuring cups? I remember the author stressing that you should weigh the flour for best results. Also, I looked at both recipes (since I have both cookbooks), and Chloe's recipe calls for baking soda and vinegar, whereas the Sticky Fingers recipe calls for baking powder. If your baking powder is too old, the cake won't rise properly. I'm not sure what else might be the problem there...but checking your baking powder seems like a good idea. If you spoon some baking powder into a bowl and cover it with hot water, it should bubble. If not, it's too old.
Reducing the oil content could change the texture and will probably reduce the moisture level of the cake. You might have to experiment to see how much you can reduce the oil and still get good results. Substituting apple sauce for part of the oil would help keep the cake moist, so that might be worth a try.
Hope this helps!