Ive been upset all day!!! Why…well you get paid way too little by your client (who I dont like btw).
And I did suspect that he was ripping you off even after you renegotiated.
Now I speak as an accountant, business woman and home cook.
What you sell is your time here. You must get paid for time spent shopping, cooking, cleaning up and delivering this slave drivers weird food requests. Usually a cook will come to the clients home and get paid by the hour including clean up time. In your case you are even using your own gas and electricity and poluting your own home. This use of rent and resourses must be charged out imo.
Also keep in mind that 18 bucks an hour for very specialised cooking skills is pretty damn low. I beg you to try getting someone to give you a quote for the same requests and I guarantee that you wont find anyone who could do it. Now, even if you found some cook who would be prepared to put in the time to make everything from scratch, follow weird recipes etc…I bet they would charge you at least $400 dollars a week minumum.
This guy is really living very well isnt he. Outsourcing all his single guy needs cheaply by the hour!!!!! Entertaining extravegantly on your hard labour and back breaking work.
I think you can make money much more easily. But, if you care to continue slaving for this client then charge him the proper market rate. eg. minimum $20 hour plus travel expenses.
I personally would make a package deal of no less than $300 week (not including food) for normal cooking etc, subject to change if the catering becomes for more people.
Good luck, you need to use those lawyer skills now to renegotiate!!!!