Brookies, a brownie and chocolate chip cookie bar

Set the oven to 350F and melt half a cup of butter in a medium bowl.

Whisk the cocoa powder into the warm butter to bring out the chocolate flavour.

Add the granulated sugar, packed light brown sugar and salt and mix to a dark sandy mixture.

Add two eggs and mix hard until the sugar all but dissolves, which gives the shiny crackly top.

Mix in the vanilla, using an electric hand mixer if you have one.

Add the flour and fold it in with a spatula until only a few streaks remain.

Stir the chocolate chips in and finish the mix.

Lightly butter the sides of a nine by thirteen inch pan, line it with paper, and spread the brownie batter into a thin even layer.

In another medium bowl, beat the granulated sugar, light brown sugar and soft unsalted butter on high for three to four minutes until fluffy.

Beat in the egg and vanilla until well combined.

Mix in the baking powder, salt and baking soda until distributed.

Add the all purpose flour and mix on low until almost combined.

Fold in the chocolate chips with a spatula, keeping a handful back, and scrape the bowl for pockets of flour.

Drop spoonfuls of the cookie dough over the brownie batter, leaving space for the brownie to peek through.

Sprinkle the reserved chocolate chips over the cookie dough.

Cover loosely with foil and bake at 350F for 20 minutes, then uncover and bake a further 20 minutes until golden on top.

They will still seem gooey and loose out of the oven; cool completely before removing and slicing.