What would happen if, the next time she starts getting pans out to make jam, you firmly say 'No, you're not making any more jam in my kitchen, you never wash up after yourself and it always end up in the bin because none of us are that keen on it'
Or the next time she brings round food that's within hours of its use by date, say 'Thank you for the thought, but I'm afraid you've wasted your money as we've got dinner sorted for tonight. Do you want to eat it for dinner or shall I pop it in our bin?
Or the next time she starts moaning about the garden not being weeded, laugh and say 'I'm sure gardening wasn't your top priority when DH was a baby, and if it was, then we obviously have different priorities'. Or if her MIL is still with you, tell her you'll bring the topic of gardening up next time you see her and ask how well your MIL got on with it when she'd just had a baby.
I have to be honest, I think I'd let her crack on with the ironing though! I do sympathise, but she's doing it because she hasn't been told it's unacceptable behaviour. Your DH obviously isn't going to tell her that so it has to come from you. You don't need to fall out with her over it, just adopt a firm, no nonsense approach. If she suggests Spanish relatives checking into the Hotel du Pip, the only answer is 'No, absolutely not. I'm not even prepared to discuss it'. And then change the subject. She won't like it, because she's been allowed to get away with it up until now, but carry on standing your ground and she'll eventually get the message that you won't tolerate her behaviour.
And if you just don't feel up to the battle, leave details about emigrating to Australia lying around!