Gather all ingredients. Preheat the oven to 350 degrees F (180 degrees C). Grease a 9-inch (23cm) square cake pan with butter, oil, or cooking spray.
Beat together milk, eggs, syrup, and pumpkin puree in a large bowl until well combined.
Pour in oats, baking powder, pumpkin pie spice, vanilla, and salt; add pecans if using. Stir well. Pour into prepared pan.
Bake in the preheated oven for 30 to 35 minutes, until the center is just set and a toothpick comes out clean. Loosely cover with foil if browning too quickly.
Serve on its own or with warm milk.