Place the all-purpose flour, pumpkin pie spice, baking powder, and salt in a medium mixing bowl. Whisk thoroughly until the ingredients are evenly distributed. Freshly ground pumpkin pie spice may be used for a stronger, more aromatic flavor. Set the dry mixture aside.
In a separate bowl, combine the nonfat Greek yogurt, pumpkin purée, room-temperature eggs, vanilla extract, and unsweetened milk. Whisk until the mixture is smooth and uniform, ensuring that no noticeable clumps of yogurt or pumpkin remain.
Pour the blended wet ingredients into the bowl containing the dry mixture. Stir gently only until the two mixtures come together. The finished batter should retain a few small lumps rather than becoming completely smooth.
Avoid excessive stirring, as overmixing can encourage gluten development and produce pancakes with a dense or tough texture. Allow the batter to stand for 2–3 minutes while the cooking surface heats.
Warm a nonstick skillet or griddle over medium-high heat, then apply a light coating of cooking spray. Once the surface is properly heated, spoon approximately 2 tablespoons of batter onto the pan for each pancake, leaving enough room between portions.
Cook for 2–3 minutes, or until the outer edges appear set and small bubbles begin forming across the tops. The appearance of these bubbles indicates that the pancakes are ready to turn.
Carefully turn each pancake and continue cooking for an additional 1–2 minutes, until the underside becomes golden brown. Because the second side cooks more quickly, monitor the pancakes closely to prevent overbrowning.
Transfer the finished pancakes to a serving plate and serve while warm. Suitable accompaniments include maple syrup, fresh whipped cream, berries, or a light drizzle of honey.