Rinse the blueberries and pat dry. Separate the eggs. Beat the yolks with the milk, honey, salt, flour and baking powder until smooth. The batter should be slightly viscous, add a little more or less milk, if necessary. Let rest 30 minutes.
Beat the egg whites until stiff and fold into the batter along with the blueberries. Heat the butter in a skillet and working in batches drop the batter by tablespoonfuls into the pan. Cook until bubbles appear on the surface, 1-2 minutes. Flip the pancakes over and cook until golden brown on the underside, 1-2 minutes. Remove and keep warm. Repeat until all the batter is used.
Serve dusted with powdered sugar.