Preheat the oven to 375. Line a muffin tin with paper liners and spray with cooking spray.
In a large bowl, whisk together the first 7 ingredients.
In a large measuring cup, combine the eggs, milk, vanilla, and oil. Stir to combine. Add the orange juice and stir.
Add the wet ingredients to the dry ingredients, stirring to combine.
Fill the prepared muffin tin with the batter. Sprinkle the tops with coarse sugar, if desired.
Bake for 15 to 20 minutes, until the muffins are golden brown and spring back when lightly touched.
Optional Glaze
Combine ½ cup powdered sugar with 1 tablespoon fresh orange juice and 1 teaspoon orange zest. Add more orange juice, a drop at a time, if needed, to reach a drizzling consistency. Drizzle over cooled muffins.