In a bowl, mix together the flour and all the ingredients up to and including sodium bicarbonate. Combine the buttermilk, butter and egg yolk and stir in.
Beat the egg white with the salt until stiff, carefully fold into the mixture.
Mix the cinnamon and sugar. Brush the raclette pan with a little butter and heat in the raclette oven. Pour enough batter into the pan to thinly cover the base. Top with the berries. Bake the pancakes until the underside separates from the pan. Serve with Nutella or cinnamon sugar.