That's what kids' menus are at restaurants. Spaghetti & meatballs, chicken fingers, mac 'n cheese, pizza, sometimes fish & chips. The same staple foods that basically all kids will eat, as a separate meal course.
My wife grew up in an immigrant family, I grew up in a half-immigrant (but largely Americanized) family. This was an element of culture shock for her. In American culture the norm is that everybody eats whatever they want to eat, and it's considered rude (sometimes even abusive) to try and control someone's food. We have obesity & diabetes rates to match. In most immigrant cultures food is considered a communal experience, where set dishes are put out on the table and it's considered rude to decline or ask for something different. You see this in restaurant customs as well, where servers at American restaurants will come around and ask each person (even the kids) what they want and then bring out individual plates, while in say Chinese restaurants the servers will go to the oldest male at the table, ask for the order, and then bring dishes out family style for everyone to eat.
It's extremely difficult to raise kids against the culture they're immersed in. Our infant will eat anything - even broccoli, celery, carrots, etc. Our 3-year-old will only eat dino nuggets, or on rare occasions, noodles or rice. When our 3-year-old was an infant, he ate everything too. But he gets snacks, occasionally lunch, and occasionally parties outside the home, and in the course of that, discovers that he really likes spaghetti, dino nuggets, and PB&J sandwiches. Hence, that is now his meal, and he knows that it is possible to have them, and he won't eat anything else when placed in front of him, even things he previously enjoyed.
(I suppose we could just not buy dino nuggets and he'd be fine; he's been fine whenever we run out and I explain that we just don't have any. But it's just not that important to me. Like I said, in American culture, the norm is that if you have the means to make yourself or your family happy, you should do it, and it's not that hard to get a 5 lb bag of dino nuggets from Costco when we go.)