I used to be way more limited and improved over time, but there are still tistic traces.
I am usually willing to experiment with something new, but once I find which variant of it I like most, I'll almost never eat any other variant. I'll make specific meals the exact same way, order the exact same thing at restaurants, and be way happier for it. I also cycle through the same meals over the span of a week for most of them. I eat the same healthyish cereal every day, because while I know cereal isn't healthy, I hate healthy alternatives and how inconvenient they are for a minor meal. I absolutely hate certain mouthfeels or taste combinations. I will always eat onion rings from any restaurant that has them.
I basically expanded my palette by redirecting my autism rather than fighting it. I blacklist instead of whitelist, while creating a set of principles that guide my behavior. I convince my autism to favor healthy foods and variety, using the ridged thinking to combat the ridged thinking.