You can put a rock or something in the bowl to take up a lot of space, so that she has to dig around the object to get all the food out. That helps when they tend to take big mouthfulls of food at one time.
You can also feed with food dispensers - there are many types of toys that are hollow with a small hole, so you can put the whole meal in the toy and your dog will have to knock around the toy to get all the food out. I LOVE these toys, especially for puppies! You can also use empty plastic bottles (gatoraide and juice bottles work best, they're a little sturdier than, say, water bottles), just put the food in the bottle and give the whole thing to your dog.