Preheat oven to 350*F. Prepare two 8-inch round cake pans by greasing them and inserting parchment circles into the bottoms.
In a medium bowl, combine the flour, baking powder, baking soda, salt and pumpkin pie spice. Whisk to combine.
2 ⅔ Cups All-Purpose Flour, 2 ½ tsp Baking Powder, ¼ tsp Baking Soda, ¾ tsp Kosher Salt, 5 tsp Pumpkin Pie Spice
In a large mixing bowl, combine brown sugar, pumpkin purée, non-dairy milk, canola oil, vinegar, and vanilla. Whisk well to combine, then add the dry ingredients to the wet ingredients and whisk to form the batter. See note.
1 ½ Cup Light Brown Sugar, tightly packed, 1 Cup Canned Pumpkin Purée, ¾ Cup Non-Dairy Milk , ¾ Cup Canola Oil, 2 tsp White Vinegar, 2 tsp Vanilla Extract
Divide the batter evenly between the pans and gently spread it out with a spatula or knife. Bake the cake layers in a 350*F oven for 24-26 minutes or until a toothpick inserted into the center of the cakes comes out clean.
Allow to cool in the pans for 30 minutes, then remove from the pans onto a parchment-lined sheet tray to cool completely, about 2 hours.