No need for all of this sneaking healthy food in by making it look like/ taste like the crap he eats.
I have two children, both with sensory issues (one ASD, one just a normal, fussy toddler, who'd live on pasta and sauce with sausages if I let him).
I have always had a routine for them, which has helped greatly in the variety of foods they both eat:
I involve them both in cooking. Toddler hates cheese, but if we make pizza together, he will eat every last bite with quite copious amounts.
They keep getting offered food they don't like in different ways - Usually, I find it's just in certain formats that they don't like them. For example, I put spinach into risottos, as salad leaves, on pizza, in lasagne, into stuffed chicken etc. One day it just clicked for my ASD (now) teen that spinach is actually quite nice. It takes something between 11 and 20-odd tries of the same food for people to get used to the taste and appreciate it, so don't give up.
If they want pudding - and unlike a PP I don't think there is anything wrong with chocolate and crisps as part of a balanced toddler diet - they have to eat a certain amount of food and they have to have tried at least a decent mouthful of something new.
We all eat together and we all eat exactly the same food for cooked meals - only breakfast is usually different as they all like different cereals and that doesn't cause me extra work. I really don't see the point in baby/ toddler food. The only thing I changed when they were just starting out was that I left adding salt, extra chillies etc. until I had portioned some off for them. My toddler would now eat a vindaloo if I let him (but I don't want to have to deal with the toilet mess the next day just yet).
They see everything. Going back to cheese, I insist that the toddler has a small amount of cheese topping where we'd usually have more. He stirs it in, because then it's "gone", but trusts all my food at the same time as he knows I won't hide ingredients from him.
Unless there is severe autism, physical or severe mental health difficulties, raising children to eat a good variety of food is not difficult. It just takes patience and a certain resilience from the parents.