Preheat the oven to 180C (350F). Grease a silicone muffin tin (or line with cases) or grease and line a small loaf tin with baking paper. Depending on size of muffin tin/cases you will have enough batter for 8 – ten brownies.
Add all the ingredients to a Vitamix or food processor and blitz until you have a smooth, fairly liquid, batter.
Divide between your muffin tin, filling only halfway up or pour into the prepared loaf tin. Scatter a few frozen berries over the top (they will sink into the batter slightly as the brownies bake).
Bake for 35 minutes or until firm on top. A skewer inserted in the centre should come out clean.
Leave to cool for 10 minutes or longer and then carefully turn out - they are quite fragile.
Dust with icing sugar and serve.
Notes
Around 180 calories per 70g serving (based on 8 servings).