butter, add the blueberries.
stir the wet mixture into the flour mixture until just combined. do not over mix.
carefully spoon the batter into the doughnut pan and bake for 14-16 minutes, until a toothpick comes out clean.
to make the icing, whisk the maple syrup and icing sugar until well blended.
pour the glaze over the cooled doughnuts and allow to set. 