In a large bowl, whisk together the flour, baking powder, baking soda, salt, and pumpkin pie spice. If you are making the spice mix from scratch, whisk the cinnamon, ginger, nutmeg, cloves, and allspice together first, then measure out 1 tablespoon.

In a second bowl, whisk the pumpkin puree, buttermilk, brown sugar, eggs, melted butter, and vanilla until smooth and evenly orange.

Pour the wet mixture into the dry ingredients and fold gently with a spatula just until no dry streaks remain. Lumps are fine — overmixing makes tough, flat pancakes. Let the batter rest 5 minutes while the griddle heats; it will thicken slightly.

Heat a large nonstick griddle or 12-inch skillet over medium heat to 350°F. Lightly brush with butter — it should sizzle and foam, not smoke.

Scoop a heaped 1/3 cup of batter per pancake onto the griddle (about 4 at a time), spreading it slightly with the back of the scoop. Cook until the bottom is golden and bubbles form and pop across the surface, 2–3 minutes.

Flip once and cook until the second side is golden and the center springs back when lightly pressed, about 2 minutes more. Repeat with the remaining batter, re-buttering the griddle between batches. Serve warm with maple syrup.