I know that the thought of your kids helping with dinner makes you groan and sigh. It definitely takes more prep work and more patience and an earlier start time, but it's so worth it to see their faces when they have helped make the meal (and they are more likely to eat it as well!). And yes, it's VERY messy but that's part of the fun and when it's all over they can help clean up as well. There are so many teachable moments here I can't even begin to count them (though I'll try).
Here are a couple of video clips of my daughter helping me make meatballs. This was a good meal for her to help with for a number of reasons: she LOVES to get dirty so this was right up her alley, there weren't a lot of ingredients to measure and pour, just about anyone can squish the meat to mix it and make the balls to put in the pan. (the background whining noise is my vacuum running, sorry for that) Autumn is a creative little soul so please enjoy the musical accompaniment to our science activity. And for the record, our meatballs were more like meat-lumps but they sure did taste good!!
Cooking is a great sensory activity, math activity, science activity, and literacy activity. You count, identify numbers, pour, measure, mix, read recipes, talk about the order of the steps (first, second, next, etc), more and less, little and a lot....the vocabulary possibilities are endless: squishy, dry, wet, rough, smooth, silky, oily, liquid, solid, gross, colors.....
So sit down with your child and figure out which meal they are going to help with. If you always tell them "no" when they ask to help you, they will eventually stop asking to help.