Ingredients to make crispy cookies and melt in your mouth?!

Ingredients to make crispy cookies and melt in your mouth?

I was wondering if anyone know extra ingredients to make cookies crispy. My grandma puts something in the cookie to make it more crispier. THE WHOLE COOKIE IS CRISPY. NOT JUST THE OUTSIDE. When i make the cookie, it does have the crispiness but not the same texture. Using the same basic ingredient, but no extra ingredient makes the cookie crispy and not melt in your mouth. So there is that one ingredient that makes the cookie crispy and melt in your mouth. Just need to find that one ingredient. So said something about using more ingredients than the Tollhouse chocolate chip, like more flour, and more ingredients. Anyone have any suggestions?...I use 2 sticks challenge butter salted. And rest are the same as toll house. I noticed that the wetter the dough is, the more crispier it is. Any suggestions?