Taking a cooking class - should I tip?

If the cook is the proprietor, definitely no. Italians in general are not tip oriented, and there are situations where they would feel slighted by the insinuation that the personal side of their relationship with you was motivated by money.

I would suggest not. We have taken classes near San Gimignano and also up at Lago di Garda and there was no suggestion or thought of tip being required or suggested at either place.

I've never considered tipping after a cooking class, either in Europe or in the USA. Some of the instructors are also owners/chefs at local restaurants, however, and other than a heartfelt "thank you" at the end of a class, the best compliment a class participant could give would be to dine at their establishment another time.

This bulletin board requires 10 characters, otherwise I would have just typed "No."

I've taken many cooking classes (both in the States and in Europe) and I've never tipped nor have I ever seen anyone tip. If you enjoy the class, post a review on TA, Chowhound, or some other foodie site.