In a large bowl, whisk oats, brown sugar, baking powder and pumpkin pie spice until they are well combined. In another large bowl, whisk pumpkin puree, applesauce, milk, maple syrup, vanilla extract and eggs until they are well combined. Pour wet ingredients into dry ingredients and stir thoroughly. Fold in pecans. Scoop batter into a muffin tin lined with cupcake liners. Top each with a pecan half.
Bake until an inserted toothpick comes out clean, about 30 minutes.
Serve immediately or store in the refrigerator for up to five days.