A ten-year-old can be the #1 assistant to the cook, and kept very busy.
Obviously we don't teach hands-on knife skills at that age, but adding ingredients to the pot/skillet/mixing bowl are appropriate.
Measuring stuff always fascinated my boys at that age. Measuring spoons, measuring cups, a pinch of this, a dash of that; it all works.
Pulsing the food processor to get the right texture is big. Boys and their toys, you know.
Smoothies are healthy and require safe prep of bananas, strawberries, etc. Buttons, noise, etc., brings the boys and their toys principle into play again.
Rolling bean burritos was big around here too. Of course you have to make sure the beans are no longer molten hot.
Butter, cinnamon and sugar on a heated flour tortilla works well.
My younger son is a sponge for kitchen knowledge. He would listen intently and store the information for future use. The elder boy just liked 'the process'. He was less concerned with detail and more apt to turn on the mixer too early and scatter the ingredients all over the place.
Learning how the child 'learns' will go a long way toward picking projects of the right nature to foster his continued interest in cooking.
Each of my boys, now ages 14 and 12, are responsible for preparing one meal a week -pretty much on their own.
Michael