In a large mixing bowl, whisk together all-purpose flour, brown sugar, baking powder, baking soda, ground cinnamon, pumpkin pie spice, and fine sea salt until thoroughly combined and free of lumps.

In a separate medium bowl, whisk together pumpkin puree, cultured buttermilk, room temperature eggs, melted unsalted butter, and vanilla extract until smooth and fragrant.

Pour the wet pumpkin mixture into the dry flour blend. Gently fold with a rubber spatula just until no dry flour pockets remain. Do NOT overmix; leave small lumps in the batter. Let the batter rest at room temperature for 10 minutes to activate the leavening agents.

Preheat a heavy non-stick skillet or cast-iron griddle over medium-low heat (approx. 350°F / 175°C). Lightly grease the surface with a small pat of butter.

Ladle 1/3 cup of batter onto the hot griddle for each pancake. Cook gently for 3 to 4 minutes, until bubbles form across the surface and the edges look set and matte.

Carefully slide a thin spatula underneath and flip each pancake. Cook the second side for another 2 to 3 minutes until puffed, springy to the touch, and golden brown on both sides.

Transfer cooked pancakes to a warm platter. Stack tall, top with whipped cinnamon butter, drizzle generously with warm pure maple syrup, and scatter toasted pecans on top!