[header] How to keep homemade cookies soft [title] Add some extra butter to the recipe. [step] Consider your sugar to butter amount carefully. If you have more sugar than butter, you will usually have a harder, flatter cookie, but if you have a little extra butter, you will have a softer, more chewy cookie. 
Even though it's a little more calories to add to your system, they will stay much softer. [substeps] If you are worried about calories and whatnot, get unsalted butter or put in a little more oil instead.