Cut the chocolate into big chunks with a bread knife and set aside in a bowl.
Mix the flour and baking powder together with a whisk and set aside.
Cream the softened butter and sugars together with an electric mixer on the paddle attachment until it begins to lighten slightly, about 5-10 minutes.
Add the egg and mix on low until incorporated. Don't overmix.
Add the rest of the ingredients except the chocolate chunks and mix until the flour is fully hydrated (No white spots).
Add the chocolate chunks and mix with a spatula. Cover the top of the cookie dough with plastic wrap and let sit overnight in the fridge.
The next day set your oven to 190°C/375°F. Line two baking trays with parchment paper.
Weigh out 75g balls of cookie dough and set on the tray with enough space in between. Sprinkle one or two flakes of Maldon salt on top of each cookie.
Bake the cookies for 11 minutes (that is the sweet-spot on my oven but your oven might be a little different). Once you see the cookies develop a nice golden brown colour then pull them out right away. Let them stand on the tray for 10 minutes.
This recipe is inspired by French pastry chef Christophe Michalak's cookie recipe.I know it's hard, but you need to let the cookies rest at least 10 minutes after baking as they'll continue to cook from the heat of the tray. It may be tempting to eat the raw cookie dough but it's never a good idea to consume raw flour. Raw flour can contain dangerous pathogens that may make you sick.