Blueberry-Maple Muffins

Preheat oven to 400 degrees F.

Coat 12 muffin cups with cooking spray.

Grind flaxseeds in a spice mill (such as a clean coffee grinder) or dry blender. Transfer to a large bowl. Add whole-wheat flour, all-purpose flour, baking powder, baking soda, salt and cinnamon; whisk to blend.

Whisk eggs and maple syrup in a medium bowl until smooth. Add buttermilk, oil, orange zest, orange juice and vanilla; whisk until blended. Add to the flour mixture and mix with a rubber spatula just until dry ingredients are moistened. Fold in blueberries. Scoop the batter into the prepared muffin cups. Sprinkle tops with granulated sugar.

Bake the muffins until the tops are golden brown and spring back when touched lightly, 15 to 25 minutes. Let cool in the pan for 5 minutes. Loosen edges and turn muffins out onto a wire rack to cool slightly.