Whisk the pancake mix, brown sugar, and pumpkin pie spice together in a large bowl.
Add the pumpkin puree, vanilla extract, and water or milk. Whisk just until combined; a few small lumps are fine.
Let the batter rest for 3 to 5 minutes.
Heat a griddle or skillet over medium heat, about 350°F, and grease lightly with butter or oil.
Pour a scant ¼ cup of batter onto the griddle for each pancake. Cook about 2 minutes, until the edges are set and bubbles cover the surface.
Flip and cook the other side for 1 to 2 minutes, until golden brown. Don't press down with the spatula.
Transfer to a plate and repeat with the remaining batter. Serve warm.
Notes
Chef's tip: Don't overmix the batter — a few lumps are exactly what you want for tender, fluffy pancakes. Nutrition (per serving, about 3 pancakes): Calories: 285kcal, Carbohydrates: 40g, Protein: 9g, Fat: 9g, Fiber: 2g, Sugar: 8g, Sodium: 510mg.Nutrition information is automatically calculated and should be used as an approximation only.