For the cake:
1. Preheat oven to 350 degrees F.
2. In a large mixing bowl, combine dry ingredients. In another large mixing bowl, stir together yogurt, eggs, vanilla sugar, and zest. Add dry ingredients to wet ingredients, and stir until combined. Add olive oil, stirring until incorporated. Fold in blueberries. Pour batter in greased, lightly floured loaf pan and bake for 50 minutes.
For the clementine syrup:
1. In a small saucepan, bring sugar and clementine orange juice to a boil, stirring constantly. Turn down the heat and allow sauce to thicken.
2. For the glaze:
3. In a medium sized mixing bowl, use a whisk or a fork to mix confectioner's sugar and bitters. You can easily substitute more clementine juice for bitters, though the bitters add a complexity that's quite nice.
To assemble cake:
1. After removing cake from the oven, allow to cool ten minutes, then drench in the clementine syrup. Allow syrup to soak into cake for ten minutes more, then invert onto a plate or cake stand. Drizzle with glaze and serve.