Add your sugars to the melted butter and stir until dissolved.

Add your salt, vanilla and egg and stir.

Sieve in your flour and cocoa, and stir until just combined.

Add 75g of each chocolate to the batter and stir. Stick in the fridge for at least 30 minutes to firm up!

Once the mix is firm, scoop onto a lined baking tray, leaving space between each ball.

Press some of your spare chocolate into the top of the balls, as when cooked, they will look more shop bought!

Put in the oven for 12 minutes until soft and a little crisp. As they cool they will firm up.