Asked To Sign An Nda After Giving 2 Weeks Notice.

I work in a cafe as a baker. I've been here almost 5 years but haven't been very influential in recipe creation I just follow the head chefs recipes. I gave notice yesterday to go to a neighboring bakery and now my old employer is asking me to sign an NDA to "protect my intellectual property and to be clear they are not your recipes." He said he isn't trying to give me a hard time but wants to make sure I don't take recipes to a competitor. I don't really plan on doing this but couldn't I change ingredients around and they aren't "his?" Couldn't i do something similar and get me or my new cafe in trouble? How can he cover all his recipes in one document? I've never been asked to sign an NDA and it's not like Coca-Cola it's a mom and pop bakery. My question is should I sign it? I'm not trying to give him a hard time either and I want to not burn bridges but I feel this move is a little aggressive? I'm not sure im willing to sign anything legal as I'm leaving. What can/should I do?