So one of the advise was using jokes or funny terms/words to make them learn. And this is one thing that I have been doing. I use my kids terms or funny terms to make them try new food. For example this:
I just bought this bun for JD last night. I said "have a custard bun" and he said "what bun? Bleargh" without even looking at it.
And then I tried again "Wow! A Hypno Bun!" And he went "where where? Wowwwwwwwwwwwww" and he brought it to school today.