I have been cooking and baking with my twins now for a little over a year. The boys are 2 and a half years old and Aaron has taken to cooking like a little chef. Connor likes it, too, but isn't into it as much. I try to spend one morning a week baking something with the boys. Aaron especially loves mixing the ingredients and keeping an eye on whatever is in the oven.
Now, I've started baking with my three nieces, ages 9, 7, and 3. They live out of state, but whenever they are up visiting, they want to come and bake with me. I enjoy teaching them how to measure and mix. In fact, my oldest niece wants me to come to her next birthday party and do a cooking demonstration for her friends!
I find cooking with the kids to be fun and exciting and who cares how a cake looks?? It doesn't need to be perfect. Children should learn how to cook at an early age so that they can sample new foods and learn to appreciate the kitchen.