Prep: Preheat your oven to 350F and grease or line a 9″x5″ bread pan and set aside.
Dry Ingredients: In the meantime, add the flour, pumpkin pie spice, baking powder, baking soda, and salt to a large bowl. Mix well and set aside.
Wet Ingredients: In a small bowl, mix the pumpkin puree, sugar, oil, milk, and vinegar until the sugar has dissolved. Form a well in the center of the dry ingredients and add the wet ingredients; mix well until no clumps remain. Pour the batter into the bread pan, smoothing the top off with a spatula.
Bake: Bake in the middle rack of the oven for 55 to 60 minutes, or until the top is golden brown, and a toothpick comes out cleanly or with minimal crumbs. Remove from the oven and carefully transfer to a cooling rack.
Make the Maple Glaze (Optional): Add the softened cream cheese and maple syrup to a medium bowl and whisk vigorously until mostly smooth. Add in the powdered sugar and whisk again, until a smooth glaze forms. Drizzle on top of the pumpkin bread once it has cooled.
Serve & Store: Allow to cool completely before slicing. Enjoy immediately, or store any leftovers in a container at room temperature for up to 5 days. You can also pre-slice and freeze this vegan pumpkin bread for up to 2 months.