Preheat oven to 350°. Spray a 8.5x4.5 loaf pan with baking spray.
Add sugar to a bowl. Use a microplane to zest clementines over the sugar. Use your fingers to rub the zest into the sugar until the oil is released and the sugar is fragrant.
Peel the clementines and cut in between the membranes and pull out the fruit. Place on a paper towel. Set aside.
Whisk flour, baking powder, and salt in a medium bowl.
Whisk the yogurt into the reserved sugar mixture. Whisk eggs in one at a time, beat vigorously until smooth. Add vanilla and orange extract.
Add the dry ingredients and whisk until you cannot see any trace of flour. Switch to a rubber spatula and stir in the oil. Add the clementine segments. And stir until just combined. Pour batter into prepared loaf pan. Sprinkle with sanding sugar.
Bake for 50 to 60 minutes or until a toothpick comes out clean. Transfer to a wire rack to cool for 5 minutes, then remove from the pan and cool completely.Her recipe calls for clementines, but if you don't have them, use an orange. The key is to rub the zest into the sugar to release the oils. It makes a huge difference in flavor. I served it with some vanilla yogurt and pomegranate arils. I also think it would be amazing with orange segments and mint. I would definitely make a few loaves of this cake and keep them in the freezer for just in case. It would be great as a base of a trifle, or grilled in the summer. So many possibilities for this simple cake.