Preheat the oven to 350°F. Lightly grease 16 muffin cups with nonstick spray or melted butter.
In a medium bowl, mix together the flour, sugar, baking powder and salt. In a separate bowl, whisk the eggs together. Stir in the oil and the milk. Add the wet ingredients to the dry ingredients and mix until combined. Stir in the cinnamon, lemon zest and blueberries.
Fill each muffin cup 2/3 full with the batter. Sprinkle the top of each muffin with coarse sugar, if using.
Bake for 20 to 25 minutes, until a toothpick inserted in a muffin comes out clean.