Step 1: Preheat your oven to 3500F (1750C). Lightly grease a 12-cavity donut pan and set aside.
Step 2: In a large bowl, whisk together the flour, baking powder, baking soda, pumpkin pie spice, and Kosher salt. In a separate medium bowl, whisk together the melted butter, light brown sugar, eggs, pumpkin puree, and vanilla extract until smooth.
Step 3: Pour the wet ingredients into the dry ingredients. Mix with a spatula until just combined. Be careful not to overmix; a few lumps are fine.
Step 4: Transfer the donut batter into a piping bag or a large Ziploc bag with a corner snipped off. Pipe the batter evenly into the prepared donut cavities, filling each about two-thirds full.
Step 5: Bake for 12-15 minutes, or until the donuts are golden brown and spring back when lightly touched. Let them cool in the pan for 5 minutes before transferring to a wire rack to cool completely.
Step 6: While the donuts cool, prepare the maple glaze. In a medium bowl, whisk together the maple syrup, melted butter, vanilla extract, and a pinch of salt. Gradually whisk in the powdered sugar until smooth and free of lumps. Add a tiny splash of milk or water if the glaze is too thick.
Step 7: Once the donuts are completely cool, dip each donut into the maple glaze, allowing any excess to drip off. Place them back on the wire rack to set before serving.