Dark chocolate has more antioxidants than other superfoods like blueberries.
Soak the seeds in 70ml (2.3 fl oz) of water for 10 minutes until they form a thick gel-like mixture.
Meanwhile, soak the dates in warm water for 10 minutes and then blitz them in a food processor with 80ml (2.7 fl oz) of water.
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Add all the ingredients in a bowl, except for chocolate, and mix until you have a dense batter.
Transfer the mixture to a 20 cm (8 inches) square baking tin, and sprinkle with chocolate chips and rosemary. Bake for 20 minutes at 180°C (355°F).
Leave to cool on a wire rack before cutting into single-serving brownie squares.