Brown the butter: Place the butter in a skillet over medium heat. Once melted, the butter will begin to foam and sizzle around the edges.Keep an eye and stir occasionally. In about 5 minutes the butter will start turning golden brown. The milk solids at the bottom of the pan will be toasty brown and it will smell nutty. Immediately transfer to heatproof bowl to stop the cooking process and allow it cool.
Prepare the pancakes: In a large bowl, whisk the flour, sugar, baking powder, baking soda, salt, cinnamon, nutmeg, and ginger together until well combined.
In a medium bowl, whisk the buttermilk, pumpkin puree, egg, melted butter and vanilla until well combined.
Add the wet ingredients to the dry ingredients, gently folding until just combined. Some lumps are okay.
Heat a nonstick skillet over medium until very hot. Add a generous amount of butter (start with 1 tbsp, adding more as needed).
Drop the pancakes into the pan by 1/4 cup, leaving enough room in between for the batter to expand.
Cook until the batter bubbles at the edges and is golden brown on the bottom. Flip and cook until batter is cooked through and golden brown. Repeat until all batter is used.
Make the cinnamon brown butter: whip the brown butter until light and fluffy, about 3 minutes. Stir in the cinnamon, salt and vanilla.
Serve pancakes with cinnamon brown butter and maple syrup.