Adjust oven rack to lower middle position and heat oven to 425 F.
Chop pears and set aside.
Make your streusel topping in a small bowl and set aside.
Mix flours, cinnamon, baking powder, baking soda and salt in medium bowl; set aside.
Mix melted butter and sugars with a whisk about 2 minutes. Add eggs, one at a time, beating well after each addition. Add vanilla extract and mix to combine.
Alternating 1/3 at a time, beat in the dry ingredients and yogurt until a smooth, thick batter just forms. Stir in your pears. Do not overmix.
Spray 12-cup muffin tin with cooking spray or coat lightly with butter. Use medium ice cream scoop and fill muffin cups half full. Sprinkle a 1/2 tablespoon of streusel over the batter. Scoop more batter over the streusel until the muffin cup is full. Sprinkle another 1/2 tablespoon of streusel over the batter.
Bake the muffins at 425 for five minutes, then reduce the oven temperature to 375 and bake for another additional 20 minutes for the large muffins (and minutes for the mini muffins). Set on wire rack to cool slightly, about 5 minutes. Remove muffins from tin and serve warm.