FOR BROWNIE DOUGH: Cream softened butter and sugars in a large mixing bowl. Add the egg, yolk, and vanilla and beat till creamy, about 2 minutes.
Combine flour, cocoa, baking soda, and salt in a small bowl. Sift into the sugar mixture. Stir till the dough is just combined. Cover and chill while preparing chocolate chip dough.
FOR CHOCOLATE CHIP COOKIE DOUGH: Cream butter and sugars in a large bowl. Add the egg, yolk, and vanilla. Beat till creamy.
Whisk flour, baking soda, and salt in a small bowl. Add to the sugar mixture with the chocolate chips. Stir till ingredients are well mixed.
TO MAKE BROOKIES: Preheat oven to 350 degrees.
Take a small portion of brownie dough and roll it into a ball. Take a small portion of chocolate chip dough and roll it into a ball. Lightly smash the balls together, and form a new larger ball of dough.
Place dough on silpat lined or lightly greased cookie sheets. Bake at 350° for about 10 minutes or until the edges of the chocolate chip cookie are golden brown.
Cool on pans for 2-3 minutes, then remove to a wire rack to cool completely.