First, preheat the oven to 375°F and coat an 8x10 inch baking dish with some cooking spray. Line the dish with parchment paper and set aside.
Next, in a mixing bowl, add oats, baking powder, pumpkin spice, and salt, mix well, and set aside.
In another shallow bowl, whisk egg until pale and creamy.
Then, add in the milk, puree, maple syrup, oil, and vanilla extract, whisk again until all the ingredients are well incorporated.
Pour the egg mixture into the oats, and mix to combine. Fold in the chocolate chips and pecans. Next, pour the oat mixture into the prepared baking dish.
Level and smooth the top and sides with a spatula so the batter is evenly distributed in the pan.
Bake in the preheated oven for about 20-25 minutes or until a knife inserted into the the middle comes out clean and the top is nicely golden brown.
Remove the dish from the oven and let it cool at room temperature. Cut the oatmeal bake into 6 even squares.
Finally, serve with plain yogurt and a drizzle of honey or maple syrup.