To caramelize the white chocolate: Preheat oven to 250 and lay a silpat on a cookie sheet. Chop up about 300g of white chocolate and spread it in the center of the silpat. Cook it for about 45 minutes, stirring every 10 minutes with a flat spatula until it’s caramel colored. When it’s done, either add it to a food processor to smooth it (on high for about 5 minutes) out or use an offset spatula to stir and smooth it by pressing down to remove the bumps. Do this for about 20 minutes until the chocolate is very smooth without bits. Pour it onto a parchment lined pan and let set overnight.

To temper the caramelized white chocolate: Melt ⅔ of the now set chocolate in 15 second increments in the microwave. Once it’s hot and almost fully melted remove and stir in the other ⅓ of the chocolate. Add 50g of fresh white chocolate (that has not been caramelized) and stir all the chocolate has melted. Pour into a parchment lined pan and let set, it should be just a few hours this time. Chop up into cubes and store in an airtight container.

To make the cookie dough: Beat together the butter, sugar, vanilla and salt until light and fluffy. Add the egg whites and beat until smooth, about a minute. Beat in the cocoa, flour and baking soda. Fold in the chocolate chunks. Set the dough in an airtight container in the fridge overnight or at least for 4 hours.

To make the cookies: Preheat oven to 350. Scoop cookie dough balls in about 1.5 tablespoons onto a parchment lined cookie sheet. Sprinkle with sea salt. Stick the pan in the freezer for about 5-10 minutes then put it straight into the oven. Bake for 10 minutes and repeat with remaining dough. Allow cookies to fully set before moving.