Preheat your oven to 350°F (175°C) and line an 8x8 inch square pan with parchment paper.

In a small bowl, combine plant-based milk with apple cider vinegar and let sit for 5 minutes to create vegan buttermilk.

Whip the aquafaba until frothy and airy, about 3-5 minutes.

In a large bowl, mix olive oil, plant-based yogurt, both sugars, pumpkin puree, vanilla extract, and vegan buttermilk until smooth.

In a separate bowl, whisk together spelt flour, pumpkin spice, baking powder, baking soda, and salt.

Gently fold the dry ingredients into the wet mixture.

Pour the batter into the prepared baking pan and level with a spatula.

Bake for 30-35 minutes until a toothpick inserted comes out mostly clean.

Cool the cake in the pan for 15 minutes, then transfer to a wire rack to cool completely for 1.5 to 2 hours.