Preheat oven to 350°. Spray 2 cast-iron muffin pans with baking spray with flour.
In a large bowl, whisk together flour, granulated sugar, baking powder, pie spice, baking soda, and salt.
In a small bowl, whisk together sour cream, oil, eggs, and vanilla. Make a well in center of flour mixture; stir in sour cream mixture just until moistened. Fold in apple and pear. Spoon into prepared muffin cups, filling two-thirds full.
Bake until a wooden pick inserted in center comes out clean, about 20 minutes. Let cool in pans for 20 minutes. Run a knife around edges of muffins. Gently remove from pans, and let cool completely on a wire rack. Garnish with confectioners’ sugar, if desired. Store in an airtight container for up to 3 days.
Recipe by Southern Cast Iron at https://southerncastiron.com/apple-pear-muffins/