He could either sit in his high chari with a tray in front to prep veggies or if you have a kids table he may be able to stand at that to do his part. I used to drag DS's little table into the kitchen to do a bit of cooking (I did bits at his little table and bits on the counter top next to him but kept talking and popping back down to him to hold his interest), until he was tall enough to stand on a chair at the counter (but watch out for falls and anything that can be grabbed, it does take a bit of thinking ahead and planning!!)
Washing veg in a bowl, tearing lettuce for salad, spooning ingredients into a bowl for salad dressing, and stirring it, rinsing rice, mixing and kneading anything like dough or meatballs. If you make sandwiches for lunch he could try to spread the butter, lay on the cheese etc and even cut the sandwich into triangles
A regular dinner knife is not usually too sharp and will do for sandwich making.
DS was 18 months old when I bought him a kid safe kitchen knife and we *really* got going in the kitchen. He uses the knife (cuts tomatoes, grapes, cucumber, mushrooms, carrots, aubergine, courgette, crusty bread...list goes on, very versatile), uses a box grater for grated cheese or carrot, used a potato peeler for potato and carrot, uses a can opener, the whizzer (obviously I am safety conscious of the blade which he may never touch). I did everything 'hand over hand' for a couple of years, teaching safety all through (I treat the knife as though it is sharp even though it does not cut skin or little fingers). These days (at 4yo) he can do much of this himself, so I use hand over hand when needed and back off a bit when I can.
He was never all that interested in baking or kneading - he appeared like he wanted to do it until it came to doing it then lost interest very quickly, but cutting fruit or veg and making real dinner (prep for stews or steamed veggies or sunday roast) he was very interested in. We've made curry, spag bol, all sorts together. These days he likes to choose which herbs or spices are added to meals, with some surprisingly nice results!
If you're interested, there are 2 safe knives I know of and have used. Pampered chef and kinderkitchen (dog knife). Both are good, we have the kinder kitchen.
I also watched a few episodes of mydaddycooks.com a SAHD who decided to get his toddler into the kitchen to make dinner. He has recipes etc and even a cook book now but it all started because he needed to mind his child and get the dinner ready at the same time. It really inspired me (and made me feel a bit rubbish!)
