1. Bake them nutella-filled chocolate chip cookies.
2. Leave the nutella and extra cookie dough in fridge for future consumption.
3. Allow the warm aroma of cookies to fill the entire apartment.
How to make your flatmates frustrated:
-Not be around to ask if we can eat a cookie, thus prolonging our torment as the smell wafts into our nostrils and terrorizes the olfactory and memory/association cortexes of our brains.
-Be in your room the whole time we’re wondering where you are to ask if we can eat the cookies, but not make any sounds and come out an hour later to our dismay and delight.