Preheat the Oven: Preheat oven to 425℉ and line a muffin tin with liners.
Mix the Dry Ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, salt, and pumpkin pie spice until well combined.
Mix the Wet Ingredients: In a large bowl, combine canned pumpkin, oil, eggs, brown sugar, and granulated sugar. Mix well.
Combine Wet and Dry Ingredients: Pour the flour mixture into the pumpkin mixture and stir until fully incorporated. Scraping the sides and bottom until there are no pockets of flour.
Pour Batter into Muffin Pan: Fill each muffin cup 3/4 of the way full, evenly distributing the batter over 12 muffins.
Bake: Place the muffins in the 425℉ preheated oven for 5 minutes, then reduce the temperature to 350℉ and bake for an additional 18-20 minutes for a total of about 23-25 minutes. The muffins are done when the tops spring back when gently pressed and a cake tester inserted into the center comes out clean.
Cool: Remove the muffins from the tins and place them on a cooling rack once they are cool enough to handle (about 5 minutes). Let them cool for another 20 minutes before glazing- warm muffin are fine, avoid glazing hot ones.
Glaze: Combine all the glaze ingredients in a bowl and whisk until smooth. Spread about 1 teaspoon of glaze over the top of each muffin.