In a medium mixing bowl combine flour, granulated sugar, baking powder and salt. Make a well in the center of the dry mixture and set aside.

In another medium mixing bowl combine eggs, milk, butter or oil, orange zest. Add egg mixture all at once to the dry mixture. Whisk lightly.

Fold in blueberries.

Spoon batter into the prepared muffins cups, filling each 3/4 full.

Bake in 350 oven for about 25-30 minutes or until golden.