In a large mixing bowl, mix all ingredients together except for blueberries and Cinnamon-Sugar mixture. Once mixed, carefully fold in blueberries.
Line muffin tin with cupcake wrappers.
Fill muffin cups halfway.
Dust the tops with Cinnamon-Sugar mixture.
Bake for 20 minutes or until toothpick inserted in the center comes out clean.
If substituting frozen blueberries for fresh blueberries, I recommend rinsing the frozen blueberries in water to help them thaw and plump, then drain and pat dry. Fold them in carefully to the batter as their skins are more likely to tear than fresh blueberries.