Preheat oven to 400°.
Place walnuts in a food processor; process until finely ground.
Lightly spoon flours into dry measuring cups; level with a knife. Combine flours and next 3 ingredients (through salt) in a medium bowl; stir well with a whisk. Stir in ground walnuts. Make a well in center of mixture.
Combine brown sugar and the next 4 ingredients (through egg) in a small bowl; add to the flour mixture, stirring just until moist. Fold in diced pear.
Spoon batter into 15 muffin cups coated with cooking spray; sprinkle batter with turbinado sugar. Bake at 400° for 20 minutes or until muffins spring back when touched lightly in center. Remove from pans immediately. Place on a wire rack. Serve either warm or at room temperature.