This is the America’s Test Kitchen recipe, by Matthew Fairman. One of the main things that I’ve found is important is giving the sugar enough time to absorb into the butter and egg. If they are not combined adequately, this can lead to a somewhat “grainy” cookie texture. But when done right, it’s a delicious combo of a brownie’s chewiness, melty soft chocolate chips, and a slightly crispy exterior.

Ingredients:

1 cup all purpose flour
1/4 cup dutch processed cocoa powder
1 teaspoon baking powder
1 teaspoon baking soda
3/4 teaspoon table salt
10 ounces bittersweet chocolate chips
3 tablespoon vegetable oil
1 tablespoon unsalted butter
2 tablespoon whole milk
1 cup sugar
2 large eggs

Dough Assembly:

Combine your dry ingredients in a bowl - flour, cocoa, baking powder, baking soda, and salt. Set aside.
In a microwave safe bowl, add 6 ounces of chocolate chips, oil and butter. Set microwave temp to 50% power, and cook for 3 minutes to melt, stirring halfway through the time.
Add whole milk to melted chocolate mixture and whisk to combine. Best if milk is room temp.
Using a stand mixer or electric handheld mixer (hand mixing with a whisk is not recommended for best results, though it’s certainly a good arm workout!), fitted with the whisk attachment, add sugar and eggs starting at medium speed then increasing to medium-high until very thick and pale, about 4-5 minutes.
Add melted chocolate/milk mixture and using a fork or whisk, combine until uniform. Then add dry ingredients, till no dry pockets remain. Lastly add 4 oz of chocolate chips to mixture and loosely combine.

Baking Directions:

Preheat oven to 300 F. Remember that many ovens are off by about 25-50 F, so getting a cheap $5-6 oven thermometer is a great way to get more consistent bakes.
On a parchment paper lined baking sheet, scoop 1 tablespoon portions of cookie dough, separating each one by 2-3 inches.
Bake for 16 minutes, making sure to rotate baking sheet halfway through baking. They will look puffy and slightly raw when done, as when they are removed from the oven they collapse giving you that characteristic cracked appearance. Cool on sheet for 30 minutes before eating.