Don't worry I won't offer meat.
It is interesting that you mentioned this, because monks normally abide by the 3 fold rule
, but then I went to that link and see that the monks have dropped a nice 'hint' about what they prefer:
What do you bring and how much?
Bring a plate or item of food for the monks/nuns to eat. What you bring and how much you bring is completely up to you. Bring something you think the monks/nuns would like to eat. You might bring enough for say four people, but there is no rule about this. If it is vegetarian this is appreciated but it doesn¹t have to be and the monks/nuns will eat whatever you are generous enough to offer them. It can be a hot dish or a cold dish. Possible suggestions for food include potato casseroles, potato salad, vegetable curry, quiche, eggs in some form, cheese dish, lentil dish, vegetable dishes, fruit salad, bread, a cake, a packet of biscuits, anything is fine. There is no expectation to bring an Asian style dish. If you like Italian, French, German, Turkish or some other style of food it is most welcome. Please feel able to bring whatever you can afford and wish to offer. (There is no need to bring cooked rice as rice is prepared by the Anagarikas, at the monastery.)
In my opinion, that is a great way to drop a hint without making a 'formal' request of what they would prefer.