Soak the rice in the water overnight (6-12 hours). Grind the rice and water mixture in blender until the rice particles in the batter reach the consistency of fine salt. Add egg, baking powder and salt to the batter, mix well and bake covered for 30 minutes in a well-oiled eight-inch iron skillet or a casserole dish (a well-seasoned iron skillet can't be beat for baking with rice).