Cooking spray $ 1 cup whole wheat flour (about 4 3/4 ounces) 1/2 cup all-purpose flour (about 2 1/4 ounces) $ 1 cup regular oats 3/4 cup packed brown sugar $ 1 tablespoon wheat bran 2 teaspoons baking soda 1/4 teaspoon salt 1 cup plain fat-free yogurt 1 cup mashed ripe banana (about 2) $ 1 large egg $ 1 cup chopped pitted dates $ 3/4 cup chopped walnuts $ 1/2 cup chopped dried pineapple $ 3 tablespoons ground flaxseed (about 2 tablespoons whole)

Preheat oven to 350°.
Place 18 muffin cups liners in muffin cups; coat liners with cooking spray.
Lightly spoon flours into dry measuring cups, and level with a knife. Combine flours and next 5 ingredients (through salt) in a large bowl; stir with a whisk. Make a well in center of mixture. Combine yogurt, banana, and egg; add to flour mixture, stirring just until moist. Fold in dates, walnuts, and pineapple. Spoon batter into prepared muffin cups. Sprinkle evenly with flaxseed. Bake at 350° for 20 minutes or until muffins spring back when touched lightly in center. Remove muffins from pans immediately; cool on a wire rack.