I have some old cookie recipes of my mother's that don't include salt in the ingredients. I have a memory of making one of her cookie recipes while she was living, and asked her why it seemed flat. She asked about the butter, and it turns out she used salted butter in those days for baking. I use unsalted. When I am trying these old recipes, should I use salted butter or is it better to use unsalted with about 1/4 tsp of salt?