Bake 1 box brownies according to package directions. I used an 8X8 pan recipe and placed it into a 10 inch round stone casserole dish. You can certainly make it in a square pan also. Be sure to use a pan with sides to keep the shape or brownie may run over sides and be too thin.
1/3 c creamy peanut butter
2-4 Tbs. milk
1 c powdered sugar
Mix and spread over cooled brownie.
Toppings: Use any combination you like
M & M's
Peanuts or other nuts
Melt 1/4 c chocolate chips in a baggie in the microwave , clip corner of bag and drizzle over top.