In a medium bowl, vigorously whisk together the all-purpose flour, baking powder, pumpkin pie spice, table salt, and baking soda to ensure even distribution of the leavening agents.

In the bowl of an electric mixer, combine the eggs, pumpkin puree, granulated sugar, buttermilk, brown sugar, and melted butter. Beat until a smooth, wet emulsion is formed.

Gradually fold the dry ingredients into the wet pumpkin emulsion in batches, mixing only until a sticky dough forms. Do not overwork the gluten.

Wrap the wet dough tightly in plastic wrap and refrigerate for a minimum of 3 hours. This critical thermal resting phase hydrates the flour and solidifies the fats, making the soft dough manageable for rolling.

Unwrap the chilled dough onto a generously floured work surface.

Using a heavy wooden rolling pin, roll the dough to an even ½-inch thickness.

Use a stainless steel donut cutter to punch out the donuts and holes. Transfer the cutouts to a parchment-lined baking sheet. Re-roll the scraps gently to use all the dough.

Pour 2 inches of canola oil into a deep, heavy-bottomed skillet or Dutch oven. (Ensure the oil fills less than half the depth of the pan to allow for safe expansion).

Heat the oil over medium-high heat until it reaches a strict 365°F to 375°F.

Carefully lower the donuts into the hot oil in batches to avoid dropping the temperature. Fry until deep golden brown on the bottom, then flip and brown the second side, about 1 to 2 minutes total per donut.

Transfer the fried donuts to a paper towel-lined baking sheet or wire rack to drain.

For the Spiced Sugar: Whisk the granulated sugar, cinnamon, and nutmeg in a shallow bowl. Toss the warm donuts directly in the sugar to coat.

For the Maple Glaze: Whisk the confectioners' sugar, maple syrup, and heavy cream in a small bowl until a thick, glossy glaze forms. Dip the top half of the cooled donuts into the glaze and allow to set on a wire rack.