Any recipe I have tried produces semi-soft cookies that are more like cakes. So how to make very crisp crispy cookies like those one can buy from the store? Looking at the product label, one can see they usually contain no moisturizing ingredient at all, just fat. So I thought one way of producing such a cookie, without an "artificial" emulsifier like lecithin, is to first make mayonnaise from a mellow oil or even ghee, if its possible, then use that and it should mix well enough with the flour, producing a smooth texture with a minimum amount of liquid (vinegar) used. Thats just an idea, the question is, how to reproduce a commercial cookie.