These fluffy, thick cookies are just the right amount of gooey in the middle and crisp on the outside and they are based on the New York City hit Levain Bakery’s cookie recipe.
Heat oven to 400ºF (200ºC) with a rack set to the lower third of the oven.
In the bowl of a stand mixer cream the butter with the brown sugar and granulated sugar until fluffy, about 2 minutes.
In a medium mixing bowl sift together the flour, baking soda, baking powder and salt. Slowly add the flour mixture until it has all been incorporated.
Add the eggs one at a time, beating until just combined after each addition.
Add the walnuts followed by the chocolate chips, mixing until just combined.
Form the dough into 6-ounce cookies, they should be just about the size of a tennis ball.
Stack two baking sheets on top of each other. Arrange 4 onto a baking sheet at a time and bake until the outside is golden-brown, but the inside is still gooey, about 12 minutes.
Remove to a cooling rack and let cool for about 15 minutes before serving.