With my step kid I've basically just told him I'm not making anything else for him if he doesn't like what I made. If he won't eat it, he can have fresh vegetables and/or last night's leftovers instead. I give him some options before I start cooking, so he knows and has some say in what dinner is.

The exception is if I make something that's objectively gross. I've had a few frozen package dinners that looked good but were outright nasty and made sandwiches instead.