Perhaps more people would sign up if 'teaching' was relaxed into 'guided discussion'? In that case, for example, the vegetarians could hang out together in Skype or just download instructions/videoes, each teaching the others some new dish to make their cooking more robust? I would then brew some vegetarian borsch (although it isn't supposed to be so).

Also, there is a difference between teaching a skill and teaching information. I could, for example, help people study Russian and Ukrainian, though I have never taught language before.