Re the Tahini – what Javizy said – also the baking removes any remaining mold. I tested the tahini on a crackers 2 days before I baked these to make sure I was ok with it.
Re the Sugar alternative – I worded it as “the equivalent of 1 cup sugar” because various allowed sweeteners are different strengths. I used Xylitol (which able isn’t hugely keen on but it’s the only one I can get in Ireland and I only have tiny amounts of it)). It is granulated and supposed to be the same as sugar in terms of strength so I used a cup but the cookies are way too sweet so I’ll adjust that next time. So you should read the recommendations on your sweetener (has to be a granulated form) and adjust accordingly.
NB I’m certainly not advocating someone bake these and eat the whole batch!! But they’re great to have on standby if you get a craving. I eat about a quarter of a cookie with a cup of lemon tea and that’s plenty for a quick sweet fix for me every few days. When you’re on the diet a few months you’ll find your sweet tooth will fade anyway… I used to have to sweeten my greek yoghurt but find it fine on it’s own now.