1Pare rind from one orange with a zester. using a small, serrated knife, peel both oranges, then cut between the membranes to separate the segments. Soak the strips of rind in iced water til they curl, then drain on paper towels. Reserve orange segments.
2Cut bread slices in half diagonally. Beat together eggs, milk, and cinnamon in a shallow dish.
Heat half the butter and oil in large skillet. Quickly dip half the bread triangles in egg mixture, turning to cover completely and add to skillet. Cook in single layer for 4 to 5 minutes, turning once, til golden on both sides. Repeat with remaining butter, oil, and bread.
3Stack three triangles of bread on each serving plate. Add some orange segments and curls, a spoonful of sour cream, if desired, and dust with powdered sugar and serve. Serves 4