How to Make It
Preheat the oven to 375°F. Line a 12-cup muffin pan with paper liners.
In a large bowl, whisk together the buckwheat flour, hazelnuts, sugar, baking powder, baking soda, cinnamon, and salt.
In a medium bowl, whisk together the milk, eggs, and butter. Add to the flour mixture and stir with a wooden spoon just until a lumpy batter forms. Gently fold in the blueberries. Mind that if you mix the batter too much, the muffins will lose their light texture.
Spoon the batter into the muffin cups, sprinkle the tops with a little sugar, and bake for about 16 minutes (slightly longer if using a conventional oven) or until golden. Take the muffins out of the pan and let them cool on a wire rack for two minutes before serving.