Line a 23cm square brownie tin with baking parchment
Preheat the oven to 170 degrees C
Sift the flour, baking powder and salt together
Place the chocolate and butter in a large bowl. Melt over a large saucepan of simmering water, stirring constantly
Once melted set to one side to cool to room temperature
In a separate bowl, whisk the eggs and then gradually whisk in the sugar
Beat the chocolate mix into the egg mix
Gently fold in the flour
Bake in the oven until almost done but still a little soft - about 28 minutes
Allow to cool in the tin
Lift out and very carefully and gently place on a cooling rack
When completely cold, cut into 16 squares