i'm trying to bake a birthday cake for my husband who has celiac. i used to make a beautiful three layer coconut cake for his birthday and would love to figure out how to make this gluten free. i just got a copy of "gluten free baking classics" by annlise roberts, after reading all the good reviews on amazon, and noticing that the book includes a coconut cake recipe. but i see that all her baking recipes seem to use canola oil as the fat. i'm used to baking with butter and wonder if it will taste health foody and less rich with the oil substitution. is there a reason why oil works better than butter for GF baking? if i switch to butter will the recipe not work? if i can switch to butter, how much butter would equal a cup of canola?