I have 4 of my grandchildren autistic, 2 what used to be called aspergers now called high functioning, as I have care of one grandson since he was 3 now 16 and is between 3 types of autism I can tell you how I personally deal with it, may not be the best but here goes,
When he was younger it was more difficult trying different textures and colours and shapes as all counted,
It had to be round. So various sausages, for meat as he couldn't take the texture of any type of fresh meat , and it had to look right,
The plate had to be a certain colour not clash,
And the texture right jelly was out,
As he always ate certain vegetables broccoli cauliflower mash potato carrots (colour) we didn't worry.
We had to experiment till we got it right.
He isn't fussy its a brain , texture, colour thing.
He eats smoked salmon because the colours right.
Now I take him shopping to help me, sometimes he chooses things probably because the packaging is right but he then tries it out and we have had success with this, I would recommend taking her shopping to see if she would choose something herself?
The smoked salmon happened when we went to the church get together and they had smoked salmon on crackers, he was only little but took one of the crackers off a plate and ate the salmon off it, we we all surprised and since then I often buy a small packet to put in his packed lunch.
As he gets older it seems easier probably because we have worked out what works for him.
He's such a blessing so kind and gentle and always respectful, it was difficult when he was younger I will say.
Being non verbal must be harder I know but she's never obstinate its just the world is different for her to communicate what works for her, lights shapes,loud noises especially has an effect , my grandson will do well because we and himself knows what works for him, he can and will live his live his way and be happy