In a mixing bowl, whisk flour with baking powder, pumpkin pie spice, and salt until well combined. Stir in pure pumpkin, nondairy milk, and sugar if using. Let batter rest for 10 minutes. Meanwhile, heat a nonstick skillet. When a drop of water fizzles on the skillet, It’s ready. Turn heat down to low and pour pancake batter into skillet, ¼ cup at a time. Cook on one side until bubbles form, about 2 minutes, then gently flip it over and cook another 2–3 minutes. Repeat until you are out of batter. Dip in maple syrup, if desired.