Preheat the oven to 180C and grease and line a 9x9in baking tin.
Mix the ground almonds with the sweetener, protein powder, cocoa powder and baking powder
Gently melt the oil and dark chocolate and allow to cool slightly. Beat together the milk and egg then pour into the dry ingredients along with the melted chocolate and vanilla. Fold in the raspberries.
Spread into the tin and bake for 20 minutes until firmed up. Leave to cool then pop out of the tin and onto a chopped board.
Meanwhile beat together the topping ingredients and chill in the fridge until needed. Spread over the cooled brownie to cover then sprinkle over the raspberries and chopped nuts. Cut into 9-12 bars then enjoy!