Butter the sides and bottom of a medium sized casserole dish or bread pan. Cover the bottom of the dish with a laver of bread. Crush the balckberries slightly and spread them out over the bread. Sprinkle the sugar/cinnamon mixture over the berries. Butter one side of the remaining bread and layer it over the berries with the buttered side up. Beat the eggs with the sugar until smooth and pale. Pour in the milk slowly while continuing to beat the eggs. Pour the milk and eggs over the bread and let it set at room temperature for one hour. Preheat the oven to 350°. Put the casserole dish into a pan and add hot water to come one inch up the side of the dish. Bake the pudding for one hour or until a probe inderted halfway from the center to the edge of the dish comes out clean. The pudding should be allowed to cool before serving.

It is best served warm but not hot.