Do they try to taste this right away?
Do they later notice patterns in the fruits and vegetables they have for lunch and snacks?
Be sure to put the knife away, out of children's reach, when you are not right there.
You can do this with a wide variety of fruits and vegetables, everything from beans to eggplants to bananas to kiwis. All have lovely surprises inside. Let the children use plastic knives to cutthem up further as they investigate and eat.
Make a scrapbook describing all the different fruits and vegetables you have explored in this way. See if children recognize them when they show up later in meals and snacks.
This is a sensory, cognitive, and fine motor experience. This is the best kind of 'cooking project" for toddlers because there is no waiting involved.