Combine dry ingredients in 1-quart mixing bowl. Mix well. Process zest with sugar in food processor or blender until sugar-fine. Add orange sugar to mixing bowl with remaining ingredients (except marmalade). Stir to combine (disregard any small lumps). Stir in currants. Chill, covered airtight, at least 4 hours to thicken. Drop 2 TBS thickened batter, 2 inches apart, onto greased baking sheets. Sprinkle with more cereal, if desired. Bake in center of 425-degree oven until tops have taken slight tinge and edges are very lightly browned, about 7-8 minutes, rotating pans if browning irregularly. Do not overbake. Cool on racks. Makes 16 (3inch) muffies.