Preheat the oven to 350°F (177°C). Lightly grease a standard donut pan with nonstick cooking spray.

In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, salt, cinnamon, and pumpkin pie spice.

In a separate bowl, whisk the vegetable oil, brown sugar, eggs, pumpkin puree, milk, and alcohol-free vanilla until smooth and evenly combined.

Pour the wet mixture into the dry ingredients.

Whisk gently just until no visible pockets of flour remain. Avoid overmixing, which can make the donuts dense rather than tender.

Transfer the batter to a large piping bag or zip-top bag. Snip off one corner and pipe the batter evenly into the prepared donut cavities, filling each approximately halfway.

Bake the Baked Pumpkin Donuts for 10–11 minutes, until the tops are set and spring back when gently pressed.

Cool the donuts in the pan for approximately 2 minutes before carefully transferring them to a wire cooling rack.

If you have remaining batter, grease the pan again and repeat the baking process.

Allow the donuts to cool for at least 10 minutes before adding the icing.

To make the brown sugar icing, combine the brown sugar, milk, and butter in a medium saucepan over medium heat.

Stir until the butter melts and the mixture becomes smooth. Bring it to a gentle simmer and cook for approximately 1 minute.

Remove from the heat. Whisk in the alcohol-free vanilla followed by the sifted confectioners' sugar. Add a small pinch of salt if desired.

Let the icing stand for about 5 minutes so it can cool and thicken slightly.

Dip the top of each cooled donut into the warm icing, allowing excess icing to drip back into the bowl or saucepan.

Place the glazed donuts on a wire rack set over a baking sheet or parchment paper.

Sprinkle with chopped walnuts while the icing is still soft, if desired.

Allow the icing to set before serving or storing.