In a mixing bowl combine the flour, granulated sugar, baking powder, baking soda, and salt. Stir with a spoon to combine and set aside.

In a larger mixing bowl combine the eggs, buttermilk, vegetable oil, orange zest, and orange juice. Stir to combine with a spatula for 30 seconds.

Gradually mix in the dry ingredients, mixing by hand just until combined. The batter will be very thick.

Cover the bowl with a towel and allow the batter to rest for 15 minutes. Preheat the oven to 425ºF during this time.

Line a 12 count muffin pan with 6 muffin liners, filling every other muffin well with batter.

Fill the liners to the top with batter. Use a butter knife to smooth the tops of the muffins if lumpy. Top with sanding sugar if desired.

Bake for 7 minutes at 425ºF, then keeping the muffins in the oven, turn the temperature down to 350ºF and bake for 13-16 minutes or until a toothpick inserted in the center comes out clean. Allow the muffins to cool in the pan.

Repeat with the remaining batter, ensuring to return the temperature to 425ºF.

For the glaze, mix the powdered sugar and orange juice together. Adjust orange juice quantity to achieve desired glaze thickness. Dip the tops of the muffins or spread the glaze over them.