Preheat a fan-forced oven to 160C / 320F (180C / 355F for no fan). Line two large baking trays with baking paper. Set aside.
Melt chocolate and butter - Fill a medium sized saucepan about a quarter of the way with water. Bring to a gentle simmer. Place a heatproof bowl on top making sure the bottom of the bowl isn’t touching the water. Add the chopped chocolate and butter in the bowl and gently stir until melted. Remove from the saucepan and allow to cool for 10 minutes.
Combine dry ingredients - Run the flour, cocoa powder, baking powder and salt through a sieve into a medium sized bowl. Use a whisk to combine.
Whip eggs and sugar - To a separate bowl add the eggs, both sugars and vanilla extract. Use an electric hand mixer to beat on high speed until mixture is thick and pale, about 5 minutes. Add 1/2 of the chocolate mixture and beat until well combined. Add the remaining chocolate mixture and repeat.
Add dry ingredients - Add the dry ingredients and use a spatula to mix until well combined. Take care not to overmix.
Bake - Use an ice cream scoop (about 3-4 tbsp) to scoop 6 balls of dough onto each baking tray spacing them well apart so they can spread. Sprinkle with sea salt flakes. Bake in the middle rack of your oven for 8-10 minutes. Use a 4-inch cookie cutter to swirl around the cookies as soon as they come out of the oven. This will give them a round shape. Allow to cool for 30 minutes before serving.
Butter - you can use salted butter for this recipe. If you do, just leave out the salt.Storage - Brookies can be stored in an airtight container for up to three days.Chocolate and butter mixture - Make sure that when melting the butter and chocolate together you stir slowly so that it doesn’t seize up.How to get round cookies - Use a 4-inch cookie cutter to swirl around the cookies as soon as they come out of the oven. This will give them a round shape.Cool down time - These cookies are really soft when they come out of the oven so letting them cool down is important to allow them to keep their shape as they’re being lifted.Nutrition - is an approximate and is based on per cookie. This recipe makes about 15 cookies.A note on measurements - this recipe is offered in weight measurements. This is in an effort to offer the most accurate way to get the best results. Cup measurements simply aren’t accurate enough for a recipe that needs precision and cup sizes differ depending on where you are in the world. Here is where you can learn more about how to measure ingredients using digital kitchen scales!