Prepare three 6" round cake pans by greasing the pans with shortening and inserting a parchment circle into the bottom of each pan. This recipe can also make two 8" cake rounds.
Preheat oven to 350* F.
In a medium bowl, combine the flour, baking powder, baking soda, salt and pumpkin pie spice. Whisk to combine.
1 ½ Cups All-Purpose Flour, 2 teaspoon Baking Powder, ¼ teaspoon Baking Soda, ½ teaspoon Kosher Salt, 4 ¾ teaspoon 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.
1 Cup Light Brown Sugar, tightly packed, ½ Cup Canned Pumpkin Purée, ½ Cup Non-Dairy Milk, ⅓ Cup Canola Oil, 1 ½ teaspoon White Vinegar, 1 teaspoon Vanilla Extract
Add the dry ingredients into to wet ingredients and whisk to form the batter. See note.
Divide the batter evenly between the pans and gently spread it out with a spatula or knife.
Bake in a 350* oven for 18-20 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.