I had a extreme picky eater (2.5 yo). He will only eat white familiar food (but he did not even eat pasta). I used to ask him to have a bite. If he did not like it he would not have to eat it. I kept my word. I did not force or punish for not eating. Since he did not see any pressure he started to try a bite of new foods. At the beginning biting counted, but later the request was biting and swallowing. He improved a lot. He started to notice he liked some foods he did not before.