Preheat oven to 350oF (180oC).Line a standard 6 cups cupcake pan with paper liners. Set aside.
To a bowl, add sugar, water, oil and vanilla extract. Whisk until sugar is completely dissolved.
Sift in flour and baking powder.
Mix until dry flour is no longer visible. DO NOT OVER MIX (mix until dry and wet ingredients are just combined).
Spoon about 1 tablespoon of batter into cupcake liner. Add 5-6 blueberries and top with about 1/2 tablespoon batter. Add 3-4 blueberries on top.
Bake in preheated oven to 350oF (180oC), rack middle position, 20-25 minutes, or until toothpick inserted in the middle of cake comes out clean.
Let cupcakes cool down in pan for 10 minutes. Then transfer cupcakes to wire rack to cool down completely.