14 tbsp unsalted butter
1 3/4 cups brown sugar
2 cups all purpose flour
1/2 tsp baking soda
1/4 tsp baking powder
1/2 tsp salt
1 large egg
1 large egg yolk
1 tbsp vanilla extract
1/4 cup granulated sugar
1/4 cup brown sugar
Preheat oven to 350 degrees and line your baking sheets with parchment paper. I imagine it might be difficult getting these cookies off the pan without the parchment paper, since they've got a sugar coating, so be sure you use the paper.
Put 4 tablespoons of the butter in a heatproof bowl and set aside. Heat the remaining 10 tablespoons in a skillet, stirring regularly and keeping a careful eye on it, until the butter is browned and smells nutty. If you use a light-colored pan, it will be easier to keep an eye on the butter, but all my pans are dark, so I checked the color of the butter by dipping some up in a spoon. When the butter is browned, pour it into the bowl with the rest of the butter and stir together.
Mix the sugars for the cookie coating together in a shallow bowl. Rub the sugars together between your fingers to get them thoroughly combined -- the mix will have a very sandy texture. In another bowl, mix the flour, baking soda, and baking powder, and set aside.
By now, the melted butter should be a little cooler, so add the brown sugar and salt, and mix until the sugar is no longer lumpy. Stir in the egg, egg yolk, and vanilla. Next, add the flour mixture and stir until just combined, making sure that the ingredients are evenly distributed.
The Cook's Illustrated recipe recommended using a bench scraper to portion out the dough, but I found it easier to get consistency in the size of my cookies just by eyeballing it. You should have enough for about 24 balls of dough, each about 1 1/2 inches in diameter. Place the cookies on the sheet with plenty of room between them, and bake (one sheet at a time in the center of the oven for best results) for about 12 to 14 minutes, rotating the sheet about halfway through. The cookies should be pulled out when they are a little underdone -- the edges will have started to set, but the middles should still look a little soft. Wait until they've set up a little more out of the oven (their residual heat will continue to cook them) then transfer to a wire rack to finish cooling off.
In my opinion, most cookies -- especially chocolate chip cookies -- are best when they are still warm from the oven, but these are, happily, just as good (and possibly better) when they are fully cooled.