If they are your friends they won't mind hearing the truth. If you lose anyone over this, it was better to find out now that they were only coming for the free stuff, right?

This Friday ask everyone what they like the best about coming to your place. After hearing your obvious praises for a few minutes, tell them that you love having them over for sure. It's really been a joy.

Let them know you have an announcement to make. You'll be taking a break from cooking on Fridays for a while until your pocketbook fills up again and you want a break too so you can join them in socializing for the whole evening. Does anyone want to take on the responsibility for cooking next Friday? If you find that the meal was always just a bonus and they'd rather have you socializing anyway, there's your answer.

Maybe someone will suggest a potluck. I know of some people that do a food competition (nothing too serious) by picking a "mystery ingredient" then everyone brings a dish that uses it in some fashion. Make it fun, get everyone involved.

If they are sympathetic to the drain on the pocketbook or only want your cooking explain that the cost to feed 12 people is prohibitive and while fun, you're still taking a break and feel free to leave a donation at the door. When you've received enough "tips" to cover dinner you'll cook again, until then people can still come over to visit but to BYO* (Bring Your Own stuff).