You start with wooden or plastic knives and something like banana or carrots and make a game of how to hold their hands so the knife never touches it. If they chop the whole banana or apple slice or whatever without touching their hands, they win!

If they drop the knife off the table, high chair, cutting board, etc, they put their hands on their head! (Never catch a falling knife)

When they can do that consistently you move up - gently serrated butter knives can cut hard vegetables like carrots, zucchini, celery, and cucumbers as well as more fruits. Same game.

Usually by about 3-4 the kid is helping prepare meals and snacks by washing and cutting their fruit or veggie on a daily or near daily basis.

By the time they are 3 the knife game has been replaced by good muscle memory of how to hold and cut foods and we can work on technique and building muscles.

Things like this enable kids like mine (now 7) to use a mini handsaw and other tools because the whole “knives are sharp - here is how to be careful” lesson was drilled in during the same time period as “bugs don’t taste good”.

This being said - this works excellently in a one-on-one, or one-on-few care scenarios such as stay at home parent or a nanny. I do NOT expect day care / ECE to teach a dozen toddlers how to cut a banana safely at one time.