Equipment
Ingredients
Wet Ingredients
- 170 g unsalted butter, cold or room temp
- 200 g dark brown sugar, packed
- 50 g granulated white sugar
- 1 large egg, room temperature
- 1 egg yolk, room temperature
- 10 ml vanilla extract
Dry Ingredients & Mix-ins
- 215 g all-purpose flour
- 8 g cornstarch
- 4 g baking soda
- 3 g fine sea salt
- 170 g semisweet chocolate chips
- flaky sea salt
Nutrition (per serving)
Method
Preheat your oven to 175°C (350°F). Grease a 9-inch round cake pan lightly with butter or non-stick spray.
Place the butter in a light-colored saucepan over medium heat. Cook, swirling the pan occasionally, until the butter foams, then quiets down, and brown specks form at the bottom with a nutty aroma (about 5-8 minutes).
Pour the browned butter (including all the toasted brown bits) into a large heatproof mixing bowl. Let it cool for 10 minutes until warm but not hot.
Whisk the brown sugar and granulated sugar into the cooled butter until combined. The mixture may look slightly gritty, which is normal.
Add the whole egg, egg yolk, and vanilla extract. Whisk vigorously for about 1 minute until the mixture becomes smooth, glossy, and slightly thickened.
Add the flour, cornstarch, baking soda, and fine sea salt. Switch to a spatula and mix just until no flour streaks remain.
Fold in the chocolate chips, reserving a small handful to press into the top later.
Transfer the dough to the prepared pan. Press it down into an even layer using your spatula or fingertips. Press the reserved chocolate chips into the top surface.
Bake for 20-25 minutes. The edges should be golden brown and set, while the center should still look slightly soft and underbaked. Do not overbake.
Remove from the oven and sprinkle with flaky sea salt if desired. Place the pan on a wire rack and let cool completely in the pan before slicing. The center will firm up as it cools.
Chef's Notes
- Browning the butter evaporates water, meaning you lose volume. The recipe accounts for this, but don't skip scraping the pan—the brown bits are pure flavor.
- The extra egg yolk adds fat and emulsifiers, creating a richer, fudgier texture closer to a brownie than a standard crisp cookie.
- Cornstarch is the secret weapon here; it softens the harsh proteins in the flour to keep the cookie cake tender even if slightly overbaked.
- For a birthday treat, pipe buttercream frosting around the rim after the cake has completely cooled.
Storage
Refrigerator: 5 days — Store in an airtight container to prevent drying out.
Freezer: 2 months — Wrap individual slices tightly in plastic wrap and foil.
Reheating: Microwave for 10-15 seconds to restore warmth and chewiness.
