Spray 6 dozen miniature muffin cups with cooking spray; set aside.
Preheat oven to 400º.
In a large mixing bowl, combine flour, sugar, cinnamon, nutmeg, baking powder, salt and baking soda.
In a separate bowl combine eggs, half and half and melted butter.
Whisk until ingredients are well combined.
Add liquid ingredients to dry ingredients in mixing bowl.
Add peaches, pears and walnuts and gently stir until ingredients are combined and the flour is worked in, but do not overmix the batter.
Spoon muffin mixture into sprayed miniature muffin tins about three-fourths full.
Bake at 400º for about 9-11 minutes for miniature muffins or 18 minutes for regular muffin pans, or until a toothpick inserted in center comes out clean. (See note below).
Cool muffin pans for 5 minutes before removing muffins from pans to wire cooling racks.
Yield: 6 dozen miniature muffins, or 3 dozen regular-sized muffins.