At age 4 I started teaching my son with a kid's knife - he had the Opinel Le Petit knife, which is slightly smaller than an adult chef's knife and has a finger guard for safety. At first I shadowed him while he was using it, then eventually started working next to him and watching. At age 7 he graduated to a regular knife.
We also have a high-powered gas range. I waited a little longer for that. I think he was around 6 when I started teaching some stovetop things. He wasn't allowed to touch the knobs for a while - I'd start the stove, adjust the flame, and put the pan on to preheat. We started with steaming, or gentle sauteing - nothing that would splatter hot grease. Pancakes were an early win, although a bit messy until he got the hang of flipping

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He was also an early master of the rice cooker. And we got him a kid-sized set of oven mitts, so he could make muffins start to finish, around age 5 or 6. We still require an adult in the kitchen at all times, though!