Into a pan, add the unsalted butter and place over a low to medium heat.

Gently melt the butter. Once melted, continue cooking until the milk solids begin to turn a dark golden brown colour. They'll pool at the base of the pan looking like crumbs and the butter should smell buttery. Remove the pan from the heat and place into the fridge to cool.

Once cool but not set firm, pour

225 g brown butter into a mixer bowl alongside the two sugars. Note: you need to melt more butter than needed in the recipe as the water content will reduce when being cooked so make sure you weigh it before adding to the bowl.

Cream together for a minute or two. We don't want this to be light or fluffy, we just want this combined.

Next, add the egg and condensed milk. Mix until combined.

In a separate bowl, add the plain flour, cornflour, baking powder, bicarbonate of soda and salt. Mix using a balloon whisk.

Add ¾ of all the chopped chocolate and the mixed flour to the mixer bowl.

Mix until everything has combined and no visible streaks of flour are left

Use an ice cream scoop to scoop out dough balls (mine were about 120g per dough ball to make 10 cookies). Press the tops and sides of each dough ball into the remaining chopped chocolate chunks and place onto your lined baking tray. The taller you shape your cookie dough ball (eg cylindrically as opposed to round) the chunkier the cookie will be.

Place the baking tray into the freezer and leave for at least 1 hour, or until frozen through.

Once frozen, preheat the oven to

160C Fan/180C/350F/Gas Mark 4.

Place a few of the dough balls onto a lined baking tray leaving plenty of space around each one and bake for 15 minutes.

Remove the tray from the oven, use a glass or cookie cutter to scoot around the edges to tidy up and let the cookies sit on the tray for at least 45 minutes before moving them onto a cooling rack. Note - moving the cookies before they have set may result in a delicious mess. If you are unable to pick them up, continue letting them cool on the tray until you are.