It may simply be that your Mom is asking for love.
I'm sure she wonders if she's done enough, herself, and the topic she brings up may be dear to her. She may wonder if she's done enough to make a difference in her child's eyes (especially since you "don't have her do anything"). Perhaps she feels, at some level of consciousness, that an effort, on your part, to show gratitude would tell her you really do appreciate all her hard work. I suspect that a special dinner, a bouquet of flowers, or any significant household project would all be good enough.
As both an Aspie and the father of Aspies, I can tell you I worry that I haven't done enough. And it's difficult waiting for my Aspie's to think to toss me any sort of emotional bone. Luckily, I know enough about how it works to not take it as personal rejection, but your mother may not be so savvy.
I bet she'd be a lot less frustrated if you schedule in a couple of buckets of shmaltz each week. Just something focussed on her and her hard work.
Watch her and see if she has a particular chore she does each week. If she grabs a broom at about 10am each Saturday morning, try and see what happens if you grab the broom at 9:30 one Saturday.
At the very least, her reaction will give you another data point you can use to figure it all out
It's not a question of selfishness. It's a question of learning how to communicate without words.