Preheat the oven to 375 degrees F. In a large bowl, whisk together the pumpkin purée, brown sugar, maple syrup, eggs, pumpkin pie spice, salt, and baking powder until smooth. Whisk in the milk.
Mix the rolled oats and chopped pecans into the pumpkin mixture. Coat an 8×8 (or similar sized) baking dish with non-stick spray. Pour in the pumpkin oat mixture and spread it evenly into the dish. Bake in the preheated oven for 45 minutes, or until the center no longer looks wet and the edges are lightly golden brown.
Serve hot right out of the oven or refrigerate until ready to serve. Can be reheated in the microwave. Top with toasted pecans, whipped cream and salted caramel sauce if desired.