1 cup unbleached all-purpose flour
1 cup whole-wheat flour
2 tsp. baking powder
1/2 tsp. table salt
1/4 tsp. baking soda
2 large eggs
3/4 cup granulated sugar
1/4 cup canola oil
1 cup natural unsweetened applesauce
Zest of 1 whole lemon
1 tsp. pure vanilla extract
3/4 cup low-fat buttermilk
1-1/2 cups fresh blueberries
Position a rack in the center of the oven and heat the oven to 400°F. Coat a 12-cup standard muffin pan with cooking spray.
In a medium bowl, whisk both flours, the baking powder, salt, and baking soda.
In a large bowl, whisk the eggs, sugar, and oil until the mixture is pale and slightly frothy. Whisk in the applesauce, lemon zest, and vanilla. With the whisk, stir in about half the flour mixture, then half the buttermilk. Repeat with the remaining flour and then the remaining buttermilk, stirring until well incorporated.
Gently fold in the blueberries.
Divide the batter among the muffin cups, filling them to the top. Tap the pan on the counter to remove any air bubbles. Bake until a toothpick inserted in the center of one of the muffins comes out clean, 20 to 30 minutes.
Let cool on a wire rack for 15 minutes. Run a knife around the muffins to loosen them and then unmold. Serve warm or let cool completely and store in an airtight container at room temperature for up to 3 days, or wrap individually and freeze for up to 3 months.