Adjust oven rack to middle position and preheat oven to 375°F. Line muffin cups with paper liners or grease with butter.
In a medium bowl, whisk together flour, baking powder, cardamom, cinnamon, nutmeg, and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, cream together butter and sugar until light and fluffy, about 3 minutes.
Beat in eggs, one at a time. Beat in vanilla.
Add ½ dry ingredients to bowl, followed by buttermilk, then the remaining dry ingredients. Stir together just until last of flour mixture is incorporated.
Stir in diced pears.
Divide batter between muffin cups, filling about ¾ full.
Bake until golden on top and a cake tester inserted into the middle of the muffin comes out clean, 18-20 minutes.
Let cool 5 minutes then transfer to a wire rack to finish cooling.
