Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking pan.
In a large bowl, cream together the butter, white sugar, and brown sugar until smooth. Beat in the vanilla and egg until well blended.
In a separate bowl, sift together the flour, baking soda, and salt. Stir the dry ingredients into the creamed mixture. Mix in the chocolate chips.
Spread the cookie dough evenly into the prepared pan. Sprinkle the prepared brownie mix over the top. Bake for 18 to 20 minutes in the preheated oven, until the cookies are golden brown and the brownie mix is set.
Cool before cutting into squares.
Interesting Facts
Chocolate chip cookies were invented in 1938 by Ruth Graves Wakefield, the owner of the Toll House Inn in Whitman, MA.
The first brownies were made in the U.S. in the late 1800s.
These brownie-blasted cookies are a delicious combination of two classic desserts.