At my school each period was 40 mins long. Assuming you're the same and there were a free period or two for your cookery club then you would need to focus on foods that are quick to prepare and cook as you have limited time. I'm thinking stir-fry, cakes, burgers etc..

You could instead arrange to have an after-school cooking club if that is allowed. It would give you more time flexibility.

If the cooking club is a once per week thing then that will limit you in terms of the kind of food you can make. Unless you have a fridge/freezer you won't be able to prep food one day, leave it and then use again it to make something the next. I personally suggest you look to try and host a cooking club two times a week to get around that problem.

You would also need to find a dedicated supplier that provides bulk goods cheaply. I would imagine you will need to work out the costs first and then figure out how much you would need to charge per student in order to run a viable club.

There's cooking equipment to consider. You may need to ask the school for money or instead rely on donations from family and friends.