ME! ME! I cannot get enough of DOBE'S!
My first Doberman is my Service Dog, Book. He's traditional black and tan, but he's 3 years old and finally keeping weight on! He still has to wear sweaters and coats in the winter, since he gets cold very easily and shivers all that weight off again!
When I was having so much trouble with his weight, my vet told me just to start feeding him lunch as well as his am and pm feeds-- nothing fancy, just more of his normal food. That plus all the training treats, running beside my bike, and about 18 months later, he's evened off at 70lbs (he's very narrow). I don't give him lunch anymore, but of course he still gets training treats with learning new behaviors.
Be careful with home-made diets, though. You could be denying her some obscure vitamin or mineral-- that could make her skinny. Make sure your vet knows you make her food, and she'll probably recommend a supplement for her.
Hope this helped!