I bet her poor tummy is used to so little...she is probably full!
I read on one of these threads that it is about a tablespoon for every pound of dog. And other threads said about 1/3 of a cup. Yorkies vary in size so much...it all depends on her weight.
I guess I would start out on the smaller side in the morning and if she eats all of that and dinner I would give her a little more.