((hugs)) for the frustrations with the cooking. My LO was MSPI and I kept him gluten free until he was one as well due to family and other food problems - so no milk, soy, wheat, oats, rye, barley - he could eat eggs, and liked them, and that was my sanity. But most other stuff was a no-no. It was TORTURE. And, yes, expensive.
I still praise and cheer when DS puts something in his mouth that he has never tried or previously rejected. Don't care if he takes it out or not, it's that he tried it that I tell him was good. And he gets a big thanks if he hands it to me rather than throw it!
Another thing that we have been doing that has been working REALLY well with DS the past month or so is taking the food that he likes and really wants (usually bread) and offer him a small piece, but tell him that he has to eat something else first to get it. So I may have a tiny piece (one bite) of bread in my hand, and a spoon of his meal (say a bite of meat or pasta) and show him the bread, and then say "Ah ah, you have to eat this one first!" and he opens his mouth wide and takes it and then grabs that piece of bread as fast as he can. After a few bites he just opens his mouth for the meal part and takes it without being told, but still grabs his bread. Tonight, he saw a piece of bread on the table within reach, picked it up, went to put it in his mouth but stopped and turned to me with his mouth open for his pasta before he ate the bread! We have done many meals this way! I'm not sure if it's "right" or not, but we never force him, never make him eat, the choice is always his and I justify it as an early start at teaching him a balanced meal - you can't just eat all bread all day every day, you gotta eat some other stuff too!