You could make Dutch Babies. Pretty much a really easy souffle, it puffs like crazy when you bake it which my kids can never get enough of. You don't really need a cast iron skillet, I use either one of my Pampered chef stone casseroles or a pie plate.
Dutch Babies
Amounts depend on cast iron skillet size.
3 C. Pan: 1 1/2 Tbsp butter, 1 egg, 1/4 c milk, 1/4 c flour
4 C. Pan: 3 Tbsp butter, 2 eggs, 1/2 c milk, 1/2 c flour
2-3 qt pan: 1/4 c butter, 3 eggs, 3/4 c milk, 3/4 c flour
3-4 qt pan: 1/3 c butter, 4 eggs, 1 c milk, 1 c flour
4-41/2 qt pan: 1/2 c butter, 5 eggs, 1 1/4 c milk, 1 1/4 c flour
Put butter in pan in pre-heated 425 oven. Mix eggs in blender, with blender going pour in milk, slowly add flour (I don't use a blender, just whisk the bejeeses out of it).
Remove pan from oven, pour batter in melted butter. Bake at 425 for 15-25 minutes, depending on pan size, until golden brown. Humps and bumps are normal. Serve directly from pan. Sprinkle with lemon juice and powdered sugar, if desired. Top with fresh fruit, berries, jam, syrup, etc. 1-6 generous servings.
Or for a simpler (although not as tasty) version of the leavening power of eggs you could make these mini cakes. While cooking the cakes rises so high that you think it will either fall over or hit the top of the microwave but it shrinks back down when you turn off the micorwave. You also get different results depending on the size and shape of your mug. This doesn't taste all that great, although my kids love it, but it's fun anyway and doesn't use a lot of ingredients or make a lot of dishes.
Single Serving, Microwave, Chocolate Cake
Mix together in a mug:
4 T flour
4 T sugar
2 T cocoa powder
Add:
3 T milk
3 T oil
1 large egg
and mix until well blended.
Place mug in microwave and cook on high for about 3 minutes. Let cool slightly.
Also, check out Good Eats with Alton Brown (if you haven't already) , he has really good visual aids