Interesting thread. DD won't eat cooked tomato (spag bol is out), hated gravy as a child - so casseroles were out, always loved sushi, olives, tapas, cheese. DS dislikes mash, mousse/cheesecake, fruit scones/buns/fruitcake.
We always had the same meals: if we had spag bol - dd had pasta and cheese; if we had lamb shanks dd would have a grilled lamb chop; if we had casserole dd would have a burger.
DD now eats everything except cooked tomato. If we have cottage pie I serve yorkies to go with ds's portion. DS will still not eat anything like christmas cake or scones.
I don't think it's helpful to cook separate meals and to pander and have come across too many adults who readily go "ugh" when confronted with something new which is very bad mannered in my opinion.
Christmas lunch here is usually: turkey, duck, good gravy, roasties, parsnips, pigs, stuffing, bread sauce, cranberry sauce, sprouts, red cabbage, runner beans (last crop - frozen for Christmas). DS skips the bread sauce and red cabbage, DH skips the parsnips and sprouts, DD skips the stuffing and bread sauce, etc, etc. Nobody turns their nose up at anything or expects special things to be made for them. Pudding is Christmas Pud and something fresh fruit based.
Nobody was ever forced to clear a plate or eat what they didn't like. Dislikes must be respected but so must the efforts of the host. "That looks lovely, you have gone to so much trouble, I must try a little". It's basic good manners and they need to be taught at an early age.