Cakes for school party?

Hello! I have a great idea for a quick and easy tray-bake that you can make without having your oven on for too long. How about trying out these Chocolate Chip Oatmeal Cookie Bars? They're delicious, simple to make, and perfect for a school party.
Chocolate Chip Oatmeal Cookie Bars
Ingredients:
• 1/2 cup (1 stick) unsalted butter, softened
• 1 cup brown sugar, packed
• 1 large egg
• 1 teaspoon vanilla extract
• 1 cup all-purpose flour
• 1 cup rolled oats
• 1/2 teaspoon baking soda
• 1/4 teaspoon salt
• 1 cup chocolate chips
• Optional: 1/2 cup chopped nuts (e.g., walnuts, pecans, or almonds)
Instructions:
1. Preheat your oven to 350°F (175°C) and lightly grease an 8x8-inch or 9x9-inch baking pan.
2. In a large bowl, cream together the softened butter and brown sugar until light and fluffy. Add the egg and vanilla extract, and mix until combined.
3. In a separate bowl, whisk together the flour, rolled oats, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
4. Fold in the chocolate chips and chopped nuts (if using).
5. Press the cookie dough evenly into the prepared baking pan.
6. Bake for 20-25 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out clean. Be careful not to overbake, as the bars will continue to cook as they cool.
7. Allow the bars to cool in the pan before cutting into squares.
These Chocolate Chip Oatmeal Cookie Bars are sure to be a hit at the school party! Enjoy!

Thank you for the suggestions. In the end, I will go with the brownies, as the cakes will be outside all afternoon and I am afraid anything containing cream cheese might become bad...

I make wonderful "Black Bottom" Cupcakes. They are a simple chocolate cupcake; before baking you add a spoonful of a cream cheese-chocolate chip mixture that sinks down to the center as it bakes to make a creamy filling. They are moist and delicious, and they only bake 20 minutes. If your interested I can send the recipe if you message me. I don't know if you're able to get cream cheese or chocolate chips, but everyone asks me to bring these...

I say crack a window and do a simple but deadly brownie or butterscotch blondie. Carrot cake is a personal favorite of mine but doesn't often go over well with children. If you must, I have a really good no bake cheesecake (which I loved as a child, but I was/am weird), which I set in a sheet pan, cut into squares and top with all sorts of fresh fruit. If you're short on time, "no bake" things often need a length of time to chill and set, so it may be worth a brief period of oven time.

try the british chocolate biscuit cake (made of cookies, chocolate, milk, chilled in fridge) or other no-bake cakes (Italian, Irish, American). perfect for this weather.
see, for example:
http://edible-ireland.com/2012/06/21/chocolate-biscuit-cake/
online.wsj.com/article/SB10001424053111904060604576574790327460286.html?mod=WeekendHeader_Rotator
Coconut 'Cheesefake' adapted by Sarah Waybright of WhyFoodWorks.com
From recipes at www.barerootgirl.com & www.bonappetit.com.
http://www.thekitchn.com/nobake-recipe-lemon-cream-icebox-cake-cookbook-recipe-188988