In a mixing bowl, combine the All-Purpose Flour (1 cup), Caster Sugar (1/3 cup), Baking Powder (3/4 teaspoon), and Baking Soda (3/4 teaspoon). Preheat your oven to 190 degrees C (375 degrees F).
In a measuring cup, combine Low Fat Vanilla Yogurt (1/2 cup), Egg (1) and Vanilla Extract (1 teaspoon).
Make a well at the middle of the flour and add the yogurt mixture. Stir until just combined.
Add Fresh Blueberries (0.5 pound) and carefully fold everything together.
Grease your donut pan with spray on oil and fill with batter until 2/3 full. Bake for 10 to 12 minutes or until golden brown.
Let donuts sit in the tray for a few minutes and transfer to a wire rack. Enjoy warm or cooled completely with some Vanilla Sugar (to taste) on top.