Heat 200ml of milk in a small pan until just steaming. Stir in ½ teaspoon of superfine sugar and 25g of butter until the butter melts.
Mix 100g of bread flour, 75g of buckwheat flour, 1 teaspoon of instant yeast, and ¼ teaspoon of salt in a large bowl. Whisk in the warm milk mixture and the yolks of 2 large eggs until smooth.
Cover and set aside for 1 hour. Whisk the egg whites until stiff, then gently fold them into the batter.
Heat a frying pan over medium heat and brush it with butter. Cook 1-tablespoon spoonfuls of batter in batches until bubbles pop on the surface and the undersides are golden brown.
Flip and cook for 1-2 minutes more, then cool on a wire rack. Repeat with the remaining batter, buttering the pan as needed.
