Melt chocolate in a bowl over a saucepan of boiling water.

Add all ingredients except hazelnuts into a high power blender and blend until smooth and silky like thick melted chocolate. Alternatively put dry ingredients in a food processor and process until a fine flour, then add wet ingredients and continue to bend until smooth.

Line a 22cm by 14cm freezer container with baking paper. Pour mixture into container. Press hazelnuts into the brownies in an even layer. Cover and place in freezer until set. Cut into 21 small rectangles, approx 5cm by 3cm.