Ingredients:

• 1 cup (2 sticks; 226 g) unsalted butter
• 1 2/3 cups (235 g) all-purpose flour
• 1/3 cup (38 g) dutch-processed cocoa
• 1 teaspoon (5 g) baking soda
• 1 cup (224 g; packed) dark brown sugar
• ⅓ cup (80 g) granulated sugar
• 1½ teaspoon (6 g) kosher salt
• 2 large eggs, room temperature
• 1 tablespoon (22 g) vanilla paste or extract
• 2 ⅓ cups (340 g) chocolate disks, dark chocolate bar broken into small pieces or chocolate chips (preferably 72% cacao), divided

Instructions:

Do ahead: Dough can be made 3 days ahead; cover and chill. Let dough come to room temperature before baking.

• Step 1
  Cook butter in a medium saucepan over medium heat, stirring often, until it foams, then browns, 5–8 minutes. Scrape into a large bowl and let cool slightly, about 5 minutes.
• Step 2
  Meanwhile, sift flour, cocoa, and baking soda in a medium OXO Mixing Bowl; whisk to combine.
• Step 3
  Add brown sugar, granulated sugar and salt to browned butter. Using an electric mixer on medium speed, beat until incorporated, about 1 minute. Add eggs and vanilla, increase mixer speed to medium-high, and beat until mixture lightens and begins to thicken, about 1 minute. Reduce mixer speed to low; add dry ingredients and beat just to combine. Mix in 1 ¾ cups (260 g) chocolate wafers with a wooden spoon or OXO Silicone Spatula. Let dough sit at room temperature at least 1 hour to allow the flour and cocoa to hydrate. Dough will look very loose at first, but will thicken as it sits.
• Step 4
  Adjust oven rack to the middle of the oven and preheat to 375°. Using a 1 ½-oz. scoop, portion out 9 balls of dough and place on a lined baking sheet, spacing about 3" apart (you can also form dough into ping pong–sized balls with your hands). Lightly press 2 pieces of chocolate on the top of each dough ball. Do not flatten; cookies will spread as they bake.
• Step 5
  Bake cookies until edges are just set but centers are still soft, 9–11 minutes. Remove from oven and carefully tap tray on the stovetop to deflate and flatten cookies. Let cool on baking sheets 10 minutes, then transfer to an OXO Non-Stick Cooling Rack and let cool completely. Repeat with remaining dough, chocolate and a fresh parchment-lined baking sheet.