Preheat oven to 375° F. Coat a 9-inch pie plate with cooking spray and set aside.
Combine oats, pecans, pumpkin pie spice, baking powder, cinnamon, and salt, in a large bowl; stir. Whisk together milk, pumpkin puree, liquid egg substitute, maple syrup, canola oil, and vanilla extract in a separate bowl. Add milk mixture to oat mixture, stirring to combine. Pour mixture into prepared pie plate.
Bake, on a cookie sheet, for 40 minutes, covering the top with foil during the last 5 minutes to keep it from getting too brown.
Cool on a baking rack for at least 10 minutes.
Place peanut butter in a small microwave-safe bowl, and microwave 10 seconds or until melted.
Cut oatmeal into wedges, and drizzle with peanut butter.
Store leftovers in the refrigerator for up to 5 days. Reheat gently in the microwave with a splash of milk to keep it from drying out.