Preheat oven to 350 degrees. Prep muffin tins with liners or grease with butter or oil.
In a mixing bowl, whisk together whole wheat flour, oats, baking powder, and cinnamon.
In another bowl, whisk together sugar, eggs, butter, milk, and applesauce.
Add wet ingredients to dry and stir well to combine.
Stir in blueberries and pecans.
Spoon batter into muffin cups, using heaping tablespoons for the mini muffins or filling to the brim for standard muffins.
Bake mini muffins for 20-25 minutes, until tops are brown and a toothpick comes out clean. Bake standard muffins for 30-35 minutes.