Sensory Disorder, Allergies, Gastritis, Autism, Anxiety.
All of these things can make for what some might refer to as a picky eater. And within good reason I believe.
Cooking activities are a great way to help your child get acclimated to new food items. Especially if you start with no intentions of making them taste or eat it.

Now, I know that sounds like the opposite of what you want to happen, but by multiple exposure alone, it helps desensitize and make non preferred foods seem less scary.
I incorporate cooking at home from time to time, and Eli’s school also incorporates cooking as well. Eli loves cooking. Whether he eats it or not, it helps to desensitize him.
I usually pick recipes of things he likes or will eat, and occasionally add in something new. If we are cooking dinner, I make sure to prepare for it early enough so there is no rush, and I have some sort of light snack, but nothing that will ruin his dinner.
Eli loves the satisfaction of the process. The family sitting down to eat what he helped cook, especially if it is a favorite meal.
We have worked up to this though.
If you are just starting out, here is a great read with tips from Autism Nutritionist Jenny Friedman.
“Fun Cooking Activities for Kids with Autism”: https://www.jennyfriedmannutrition.com/blog/cooking-with-an-autistic-child