Preheat the oven to 180°C/Gas 4. Line a shallow baking tin with baking parchment.
Put the honey and vanilla seeds in a small pan and heat gently, stirring to combine.
Place the oats, puffed rice, bran, almonds and seeds in a mixing bowl. Pour in the honey mixture and stir well. Transfer to the prepared tin, sprinkle with a pinch of salt and bake for 25–30 minutes, stirring now and again to ensure even toasting, until crisp and golden.
Once cooked, set aside to cool slightly, then break into small pieces if necessary. Stir in the berries and, once cold, store in an airtight container until wanted.