Instructions

Make the chocolate crumb

1. Heat oven to 300F. Line a sheet pan with parchment or a Silpat.
2. Combine sugar, flour, cocoa powder, cornstarch, and salt in the bowl of a stan mixer fitted with a paddle attachment, and paddle on low speed until mixed.
3. Add melted butter and continue to paddle on low speed until the mixture starts to come together in small clusters
4. Spread the clusters on the lined sheet pan. Bake for 20 minutes, breaking them up occasionally. The crumbs should still be slightly moist to the touch at that point; they will dry and harden as they cool.
5. Let the crumbs cool completely before using. They will keep in an airtight container int he fridge or freezer for up to 1 month.

Make the cookies

1. Brown your butter, then place into a large mixing bowl to cool slightly.
2. After cooled, in the mixing bowl, combine the brown butter, brown sugar, and granulated sugar. Use a silicone spatula to mix together. Add the egg and vanilla and mix well.
3. Add in the flour, baking soda, salt and fold until no streaks of flour remain, being careful not to overmix your batter. The dough should be soft but not sticky, so when you touch it with your finger, it gives just a little.
4. Fold in the chocolate crumb until evenly distributed. Do not over mix. Cover the bowl and place it in the fridge to chill for at least 1 hour (and up to overnight).
5. Preheat the oven to 350°F. Line two baking sheets with parchment paper. Remove the dough from the fridge and allow it to soften at room temperature until it’s scoopable (about 20 minutes). Use a 1 ½ ounce cookie scoop to portion out equal amounts of dough. Place on the prepared baking sheets, spacing the dough 2 inches apart.
6. Bake until the cookies have puffed up and are light golden brown around the edges but still somewhat soft in the middle, 12 to 13 minutes. Remove the baking sheet from the oven, sprinkle with flaky sea salt (if using), and allow the cookies to cool slightly on the baking sheet before serving.