Step 1

Preheat the oven to 415°F (210°C). Line a baking sheet with parchment paper.

Step 2

In the bowl of a stand mixer fitted with a paddle attachment, beat the browned butter, brown sugar, granulated sugar, and vanilla extract until well combined, about 4 minutes.

Step 3

Add the eggs and egg yolk one at a time, beating after each addition until fully incorporated. Add the cake flour, all-purpose flour, cornflour, baking soda, and salt. Mix until just combined.

Step 4

Stir in the chocolate chunks, chocolate chips, and walnuts by hand. The dough will be a bit more crumbly than a typical cookie dough, but if you feel it won’t hold together, add 1 to 2 tablespoons of water.

Step 5

Divide the mixture into 8 large mounds and place them on the prepared baking sheet. Make the mounds tall and large, just how you want them to look when they finish. (They don’t spread much while baking.)

Step 6

Bake for 8 to 11 minutes or until golden brown. Remove the sheet from the oven and allow the cookies to cool on the baking sheet for at least 10 minutes. Enjoy the cookies while still warm and gooey.