What is an appropriate age to let kids start helping (with small tasks, of course) in the kitchen? & What are some fun but healthy recipes to make with young kids?

My oldest is 4 so still pretty young to help with a lot but I do make a point to have her help me.  I let her stir things and I pre-measure ingredients for her to add.  I let her do other things like tenderize meat and use cookie cutters to cut out cookies.  There's so much they can "help" you with!  I have a passion for cooking and really enjoy sharing it with her so anytime I'm cooking I ask myself each step of the way if this is something she can help me with.  Of course, she has to stay away from the oven/stovetop but there's still tons of stuff.  Even just identifying foods in the refrigerator and having her gather things for me is enjoyable to her.  Salads are easy, fun and healthy to make together... don't forget about fruit salad too!  Making salad dressing for the salads is great too since it adds a different aspect to it than just chopping fruits & veggies.  Pizzas are also fun to make (fruit pizza too!!).