Faddy Eaters or is it just my cooking?

Well I picked up the book "Can't Eat , Won't Eat" by Brenda Legge, from the library yesterday and already I'm hooked. She is describing my son to a tee. Eats KFC happily once a week but has gone off chips at home. Loves roast dinner but will only eat it on Sundays with a sausage on the side. Otherwise he doesn't like sausages or peas the rest of the week. Eats chicken burgers for lunch every day for a month and then has "never ever liked them", In fact I'm told "I 'forced him to eat them'. Neither does he like Walkers crisps,won't eat a large bag of popcorn because there is too much in the packet. The list just goes on and on
I thought I was going mad.Panic would set in at the thought of making tea. We had a freezer full of food but on past experience it was unlikely my son would like anything.
Initially the ritual of getting up from the tea table and walking out in disgust only happened when my husband wasn't there. I looked at it as a sign of defiance. It wound me up and I had to keep tight lipped so that the rest of us could enjoy a peaceful teatime without anger and aggression.
Latterly my sons 'pickiness' for want of a better word has worsened and has been witnessed by my husband and my parents. In a way I'm glad it isn't just me! You wonder if you are doing something wrong and can be made to feel  like an ineffective parent with an undisciplined child.
He eats chocolates, crisps, some biscuits, cornettos but refuses point blank the offer of a healthy jacket potato or a sandwich. I thought of banning sweets until he ate properly. It doesn't work and Brenda's book is testimony to that, your child just eats even less.
Today we went into a supermarket. Immediately my son walked out because it was too loud and he said he didn't like sandwiches. We've had this before.He doesn't mean sandwiches I learned today in Asperger speak it means " I don't generally like cold food for lunch. I prefer hot and would like a cheeseburger and chips with Fanta please" I got it right and he was happy!
Then one day the weather was so lovely we decided to have a barbeque in the garden. I watched as my husband got out the sausages and beefburgers. "He won't eat them " I thought as my son has refused both for weeks. Tea time came and he promptly tucked into a beefburger and two sausages!
Aspergers takes a lot of understanding and I don't think that I will ever fully get there but I'm trying my best and would love to hear from any of you out there who have similar  experiences!