Dough: In a medium bowl sift together flour, baking powder and salt. Rub in butter until the mixture resembles coarse breadcrumbs. Stir in milk a little at a time and mix well. Knead briefly. Set aside.
Filling: In a medium bowl stir together cherries, sugar, cinnamon and lemon zest until well mixed.
On a floured surface roll the dough into a rectangle 1/2 cm thick. Brush with melted butter. Spread the cherry filling evenly over the surface of the dough leaving 1cm around the edges.
Roll up the dough starting at a short end and pinch together all the edges so that the juice will not escape. Wrap roll in a paper towel or cheesecloth and tie loosely.
Place in a steamer or colander over boiling water then cover and steam for 90 minutes until dough is firm. Remove cloth, slice and serve.