My son loves to do "experiments." Lucy's daughter enjoys the same thing, with a cooking/baking angle:
My 3 1/2 year old wanted to help me make bran muffins. I had her pour the flour and sugar, crack the eggs and so on. She really wanted to do much more than that and get her hands dirty (ie, stick her fingers in the mix, lick them and then do it again). So, I put a towel on the kitchen floor and set out several bowls and measuring cups and spoons. I filled some with bits of sugar and flour and cinnamon, some with milk and water. I also gave her some raisins (other healthy bits like banana chips and chocolate chips could be used as well). While I finished up the muffins, she was quite happy playing with her own mixture. And I didn't worry about her taking nibbles of her creation (no raw eggs involved). Next time, I think I'll give her a little bowl of sprinkles.