Preheat the oven to 180^oC [350^oF]. Place the butter, sugar and orange rind in the bowl of an electric mixer and beat for 6 minutes until light and creamy. Add the eggs and beat well. Fold through the sifted flour, baking powder and buttermilk. Gently fold through the raspberries and pistachios.

Line a 9X26cm loaf tin with baking paper. Spoon in the mixture and bake for approximately 55 minutes until cooked through. Allow to cool in the tin for 5 minutes. Turn out onto a wire rack and cool completely.