I agree with what Dollface suggests. It's just that since your GSD is already 2 years old and has the bad manners to actually jump up on a counter

you might have to resort to some drastic actions. I don't like cats walking around, I definitely would be ticked off if a dog jumped up to steal food

You've had her for just over 2 months and this is a continuation of an original habit probably from her first home, so it's likely going to be rough to break her of her 'disrespect'. In short, she's not respecting your 'authority' over the food distribution.
Figure that this will take time and it won't change overnight, unfortunately.
You could either take the leash and tie her to something solid with a pad/bed next to it when you start preparing food or go ahead and crate her nearby. This will become her 'place' to go/be at when you are handling food. If she makes a fuss, tell her "NO-Quiet". A spray water bottle might come in handy to settle her down once she's been 'told.'
Basically, she has to learn respect before you allow her the gift of being free when you prepare or eat your food. I've helped other dog owners to do this. Sometimes, it's only taken 3 days before the dog goes to its 'place' to stay there on its own. Others have taken months :rolleyes:. Reinforcement is necessary occasionally, especially when the dog 'checks' to see if you still are in charge ;)
I don't like dogs staring at me or my food, so mine naturally vanish to their beds by now :) I also feed them AFTER we eat--taking our sweet time. Which supposedly implants that I'm superior to them :rolleyes: I don't know if it's true, but I never have food issues with my dogs, so it could be :P :)
I hope this helps out. Good luck :)
toodles