In a medium bowl or measuring jug, combine the soy milk, apple cider vinegar, and vanilla extract. Stir and let sit for 5 minutes to curdle slightly.
In a large mixing bowl, whisk together the flour, brown sugar, baking powder, cinnamon, allspice, ginger, and salt.
Add the steamed pumpkin and the buttermilk mixture to a blender. Blend until smooth.
Pour the blended pumpkin mixture into the bowl of dry ingredients. Whisk until just combined—do not overmix.
Heat a thin layer of vegetable oil in a nonstick skillet over medium heat. Scoop about 2–3 tablespoons of batter per pancake into the skillet, spacing them apart. Cook for 2–3 minutes, until bubbles appear on the surface. Flip and cook for another 1–2 minutes, until golden brown and cooked through.
Transfer to a plate and keep warm. Repeat with remaining batter. Serve warm with whipped coconut cream and maple syrup, if desired.