Combine the flour, brown sugar, baking powder, ginger, baking soda, salt and cinnamon in a large bowl. Cut the butter into the flour mixture until crumbly using a pastry blender or the tines of a fork. In a small bowl, combine the molasses, milk and egg yolk until smooth stir into the crumb mixture until a thick dry dough forms. Add additional milk a little at a time until the dough is still thick but not as dry and easily knead-able. Turn dough onto a floured surface knead briefly. Pat into an 8-inch circle and cut into 4 wedges. Stack the wedges and flatten them down again into an 8-inch circle. Cut into 8 wedges.
Separate wedges and place on a parchment-lined baking sheet. Beat egg white with 1 tablespoon water and brush on top of scones. Bake for 15-18 minutes, or until the scones are well-browned on top. Transfer to a wire rack and allow them to cool. Combine the powdered sugar and cream or milk. Transfer to a zip-top bag with the corner snipped, or to a disposable piping bag. Drizzle glaze over cooled scones. Let stand until the glaze is set, about 1 hour.
Package scones in a festive holiday tin for gift-giving.