Preheat your oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease with cooking spray.
In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and all the spices. Set aside.
In a large bowl, cream together the softened butter and brown sugar until light and fluffy, about 2-3 minutes.
Beat in the eggs one at a time, then stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined – be careful not to overmix!
Gently fold in the diced pears.
Divide the batter evenly among the prepared muffin cups, filling each about 2/3 full.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.