Put the mash in a mixing bowl together with olive oil and chia seeds. Mix well. Leave to set for 15 minutes.
Add cardamom, buckwheat flour, and baking powder into the mixture and stir well.
Add the blueberries right before putting the dough in the oven. If you use frozen berries, make sure to take them out of the freezer at the very last minute to prevent them from melting.
Line a loaf tin with greaseproof paper and pour the dough into the tin.