My partner is dieting (which is a yeast free/sugar free diet), and his birthday is soon. I was wondering if anyone had any delicious sugar free cake recipes? Any suggestions would be much appreciated.
Thank you.

Your subject title is "fat free" and your post asks for "yeast/sugar free" - pray tell what ingredients are then left to make a cake or bread with except flour....

Diet soda pop cake (doctored mix) recipe:
(Could substitute a Pillsbury reduced calorie cake mix.)

http://www.recipezaar.com/4-Points-Diet-Soda-Cake-130793

Sugar free, fat free cake recipe:

http://www.fatfree.com/recipes/cakes/sugar-free-cake
Uses prunes and banana to replace fat.)

Sugar free, vegan carrot cake recipe:
(Uses orange juice concentrate in place of sugar, and dates in place of fat.)

http://vegetarian.about.com/od/vegancakerecipes/r/sugarfreecarrot.htm

Fat free, sugar free cheesecake recipe:

http://www.cooks.com/rec/view/0,1825,159178-245193,00.html

Sweet N' Low Gingerbread snack cake mix:
(Sugar free, low fat.)

http://healthyheartmarket.com/gingerbreadsnackcakemix.aspx

HTH