Preheat oven to 375°F.
Line a 12-cup muffin tin with paper liners or lightly grease each cup.
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
In a separate medium bowl, whisk the eggs until smooth.
Add the milk, oil, and vanilla to the eggs and stir until well combined.
Pour the wet mixture into the bowl with the dry ingredients.
Stir gently just until the batter is mostly combined. Do not overmix.
Toss the blueberries with 1 tablespoon of flour to help prevent sinking.
Fold the floured blueberries gently into the batter.
Spoon the batter evenly into the 12 muffin cups, filling each about 3/4 full.
In a small bowl, mix 2 tablespoons sugar with 1/4 teaspoon cinnamon if using.
Sprinkle the cinnamon-sugar mixture over the tops of the muffins.
Bake for 20 to 25 minutes, or until the tops are golden and a toothpick inserted in the center comes out clean.
Let the muffins cool in the pan for 5 minutes before transferring to a wire rack.
Serve warm or let cool completely and store in an airtight container.