Brownie Layer:
Cookie Layer
Preheat the oven to 160°C (320°F) and line a baking pan.
Melt the unsalted butter for the brownies in a pan over medium heat until golden brown.
Whisk together the sugar, eggs, and vanilla until pale and bubbly. Mix in the combined melted chocolate and browned butter until smooth. Fold in the flour, cocoa powder, salt, and chocolate chunks.
Brown the unsälted butter for the cookie layer in a separate pan until golden brown.
Beat the browned butter with both sugars until creamy. Add the egg and vanilla, then fold in the flour, salt, baking soda and chopped chocolate.
Spread half the brownie batter in the pan, layer half of cookie dough in the middle, add the remaining brownie batter, and top with the remaining cookie dough in thin disks. Bake for 25-30 minutes, or until a toothpick comes out with moist crumbs. Let it cool, then refrigerate for at least 2 hours before slicing.
