Preheat oven to 350℉. Line an 8x4 inch loaf pan with parchment paper.
In a blender, pulse together the pumpkin puree, oats, maple syrup, eggs, yogurt, vanilla, cinnamon, pumpkin pie spice, salt, baking soda and baking powder until combined. Transfer mixture to the loaf pan and spread out evenly. Bake for 45-55 minutes or until toothpick comes out clean. Let it set in the pan for 10 minutes and then transfer to a wire rack to cool completely before icing.
Brown Butter Icing:
Melt your butter in a small pot, on low, for 4-5 minutes - until it turns golden brown in color.
In a small bowl, whisk together the powdered sugar, cinnamon, brown butter, milk, vanilla and salt until smooth. Spread icing on top of cooled loaf.