I'm mad at my GF for her pickiness with food
Why would you be mad at your girlfriend for that?
She refused to try my dinner menu, which is full of rare foreign foods. She's too picky with food.
It can be frustrating when people don't want to try your food but you shouldn't force people to eat it when they don't want to. They might throw up if they are forced to eat it.
She should appreciate my cooking and its uniqueness.
It's a shame she doesn't like what you cook, but you should respect what she wants to eat. And maybe eventually her tastes will change.