If you visit Hagrid, you will likely get offered rock cakes. While his may break your teeth, these soft biscuits are much more enjoyable.
Oatmeal Raisin is a classic cookie that is really simple to bake. This recipe yields a few dozen, so great for baking for a crowd.
Making granola bars from scratch is easy to do, and so much healthier than the store-bought version. You can also customize to your tastes.