Slowly melt the chocolate and butter into a large bowl over a pan of simmering water.
Once melted, remove the bowl from the water and add the sugar.
Whisk the ingredients fully using a hand mixer to remove any lumps.
Add each egg one at a time into the mixture and whisk through before adding the next, finishing off with the extra yolk.
Gently fold in the ground almonds using a large metal spoon, then sift in the flour and baking powder and continue to slowly fold in until incorporated into the mixture.
Pre-heat the oven to 170C (fan-assisted)
Stir in the chocolate chips, pistachios and orange juice.
Pour the mixture into a 23cm square brownie tin and place into the centre of the pre-heated oven and bake for 25-30 minutes (27 minutes was the ideal time for my oven but others may vary).
Once ready, remove the tin from the oven and leave to cool for 30 minutes before turning onto a large enough board for dividing.
Recipe by Food & Fitness Always at https://foodandfitnessalways.com/chocolate-pistachio-brownies-3949/