Step 1

Adjust an oven rack to the middle position. Preheat the oven to 350° F. Line three baking pans (I find that commercial-grade 12" x 17" rimmed pans give me the best results with this recipe) with aluminum foil, dull side up. This helps create the crinkles in the cookies and lends an extra-crisp, golden brown bottom.

Step 2

In a small bowl, whisk the flour, baking soda, and salt.

Step 3

In the bowl of a stand mixer fitted with a beater blade, beat the butter on medium until creamy, about 2 minutes. Add the sugar and brown sugar and beat on medium until light and fluffy, 2 to 3 minutes. Add the egg, vanilla, and water and mix on low to combine. Add the flour mixture and mix on low until combined. Add the chocolate and mix on low into the batter.

Step 4

Form the dough into balls weighing 3-1/2 ounces (100 g) each. This is approximately a heaping 1/3 cup each. I wanted my cookies to match Sarah's as much as possible and measured each dough ball with a kitchen scale. If you make the dough balls smaller, you won’t get as many ridges on the outer layer, and your centers won’t be as gooey. Place four balls an equal distance apart on prepared pan and transfer to the freezer for 15 minutes before baking. Do not skip freezing the dough, as it's essential in keeping the dough from spreading too much, and aids in the creation of the crinkly outer layer. After putting the first baking pan in the oven, put the second one in the freezer.

Step 5

Place the chilled baking pan in the oven and bake 10 minutes, until the cookies are puffed slightly in the center. Lift the side of the baking sheet up about 4" from the oven rack and let it drop down against the rack, so the edges of the cookies set and the inside falls back down. To quote Sarah, "this will feel wrong, but trust me". After the cookies puff up again in 2 minutes, repeat lifting and dropping the pan. Repeat a few more times to create ridges around the edge of the cookie. Bake 16 to 18 minutes total, until the cookies have spread out and the edges are golden brown but the centers are much lighter and not fully cooked.

Step 6

Transfer the baking pans to a wire rack; let cool completely before removing the cookies from the pan.