3/4 cup nonfat or low-fat buttermilk
3/4 cup packed light brown sugar
1/4 cup canola oil
2 large egg
1 cup mashed ripe banana (about 3 medium)
1 1/4 cup whole-wheat pastry flour
1 cup all-purpose flour
1 1/2 tsp baking powder
3/4 tsp ground cinnamon
1/2 tsp baking soda
1/2 tsp salt
1/4 tsp ground nutmeg
1 1/4 cup blueberry, fresh or frozen
Preheat oven to 375F. Coat a 9-by-5-inch loaf pan with cooking spray.
Whisk buttermilk, brown sugar, oil and eggs in a large bowl. Stir in mashed bananas.
Whisk whole-wheat pastry flour, all-purpose flour, baking powder, cinnamon, baking soda, salt and nutmeg in a medium bowl.
Fold the dry ingredients into the wet ingredients and stir until just combined. Fold in blueberries. Transfer the batter to the prepared pan.
Bake until the top is golden brown and a wooden skewer inserted in the center comes out clean, 50 to 60 minutes. Cool in the pan for 10 minutes, then turn out onto a wire rack. Let cool for about 2 hours before slicing.
Preheat oven to 400F. Coat 12 (1/2 cup) muffin cups with cooking spray or line with paper liners. Divide the batter among the muffin cups (they will be full). Bake until the tops are golden brown and a wooden skewer inserted in the center of a muffin comes out clean, 20 to 25 minutes. Cool in the pan for 10 minutes, then remove and let cool on a wire rack for at least 5 minutes more before serving.
Ingredient note: Whole-wheat pastry flour, lower in protein than regular whole-wheat flour, has less gluten-forming potential, making it a better choice for tender baked goods. You can find it in the natural-foods section of large supermarkets and natural-foods stores. Store in the freezer.
To Make Ahead: Wrap and store at room temperature for up to 2 days or freeze for up to 3 months