Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking dish with butter.
In a large bowl, cream together the butter and sugars until light and fluffy. Beat in the egg and vanilla extract.
In a separate bowl, sift together the flour, baking soda, and salt. Gradually add the flour mixture to the creamed mixture, stirring until just blended.
Stir in the chocolate chips.
Press the dough into the prepared dish.
Bake in preheated oven for 20 to 25 minutes, or until the edges are golden brown.
Allow to cool before cutting into bars.
Interesting Facts
This recipe was originally developed by the Amish people of Pennsylvania.
These cookies can be stored in an airtight container for up to a week.