I've thought about this a lot lately. Not so much with cooking and baking (although I do all that but not as much as you by the sounds of it!) but just in terms of the attention and time that our two boys get with us, trips out swimming, museum visits, one on one time, movie nights, meals out etc. I think there's a lot of truth in what people have said, to them it's the norm, why would they even question it? It's not a treat to them, it's not something they even have to think about because we made it that way. It's hard. I sometimes feel utterly underappreciated (don't most mums though?!). BUT then I remember that when they are older they will look back and have happy memories with me and DH. They will remember trips with DH camping, walks with mummy to find leaves and sticking and glueing to make autumn pictures, collecting holly to help make the Christmas wreath, baking with me, making jam etc. They have a lot of time with us and get a lot of input. Could you try involving them in the baking and cooking a bit so they get that time with you and also appreciate the hard work that goes into all that.
Another thing I realise is that children don not have a clue how monotonous all the things we do are. Fore example, my DS1 is 6, he thinks it's amazing fun to mop the floors, spray the worktops and clean them, he would love to use the iron if I let him (which I don't!) but what I mean is, all the mundane tasks that pile up around us every day actually look quite fun to kids (hence all the toy hoover, kitchens and fake plastic irons etc.) They don't realise quite HOW hard it is and how by the time you're 30 with kids that those things aren't FUN and exciting! I swear DS1 thinks being a stay at home mum must be the most fun thing in the world. Playing with gadgets all day long, baking, sticking and colouring. He must wonder why the hell mummy and daddy are so bloody knackered by it all! He will get it one day, but not yet and that's fine by me.
At your children's ages, there's no reason why a little verbal reminder on quite how much you do wouldn't sink in. They need to know that Mum made this and it took all afternoon. They need to know that mum made it 'for them' otherwise it just fades into the background. The truth is, they are children and it's not in their nature to be eternally grateful and full of thanks for the things we do.
Sometimes my DS1 tries to ask for more time with me, more input, constant activities with me and these are the times when I sometimes remind him 'we spent all morning doing whatever with him and mummy needs to do this now.' There's no harm in not doing those things all the time. If you're not enjoying it or you need time away for yourself then take it.
I feel for you because the main reason I try to go into overdrive by doing so many things with our children is that I never got that in my childhood. I never felt valued or listened to. Never got attention or affection. I also never felt loved or safe and these are the things I want more than anything to convey to my boys that no matter what I am on their side and I would fight to the death for them. I never had that. Never had any one on one time. Never knew when the next beating or huge argument was going to blow up. It's hard trying to undo the past and give your children the exact opposite of what you had.
For what it's worth, you sound lovely. I wish you had been my mum!