Heat oven to 200 degrees C. Grease bottoms only of 12 muffin cups or line with patty cups.
In a medium bowl, combine flour, sugar, baking powder, orange zest and salt; mix well. In a small bowl, combine orange juice, oil and egg; blend well. Add dry ingredients all at once; stir just until dry ingredients are moistened (batter will be lumpy.)
Fill cups 2/3 full. Bake for 20 to 25 minutes or until toothpick inserted in centre comes out clean. Cool 1 minute before removing from pan. Serve warm.