1. Preheat an oven to 180°C.  Grease a 23cm long x 10cm wide x 8cm loaf pan with melted butter and line the base and sides with non-stick baking paper.
2. Sift flour, baking powder, bi-carbonate of soda, salt and cinnamon together in a large bowl.  Stir in sugar and 1 cup frozen raspberries. Whisk banana, buttermilk, egg and melted butter in a jug.  Using a large metal spoon, fold banana mixture into dry ingredients.  Spoon mixture into prepared pan.  Sprinkle with remaining 1/3 cup frozen raspberries, slightly press into mixture then sprinkle with 3 tsp brown sugar.  Bake for 1 hour or until a skewer inserted in the centre comes out clean.  Cool in pan for 5 minutes then turn onto a cake rack to cool.  Store in an airtight container, serve at room temperature or toasted and lightly buttered.

Per serve: 1141kJ, protein 5.5g, total fat 11.6g (sat. fat 7.2g), cholesterol 52.5mg, carbs  34.9g, fibre 3.5g, sodium 484.4mg. GI estimate: medium