Wash the blueberries, sort them out and let them drip off on kitchen paper. Mix flour, sugar, baking powder and baking soda in a bowl. Wash the orange, grate dry, peel the peel into zests, cut finely and add. Put the egg, oil and buttermilk into a high mixing bowl and mix with the whisk of the hand mixer. Stir the buttermilk mixture into the flour mixture with the dough hooks of the hand mixer. Stir in the poppy seed filling, fold in blueberries.
Tear parchment paper into 12 squares (each approx. 15 x 15 cm). Line recesses of a muffin tray (12 recesses) with parchment. Spread the dough evenly. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) on the middle shelf for 20-25 minutes, remove. Take the muffins out of the tins and let them cool on a cake rack. Dust the muffins with icing sugar
Waiting time 1 hour