Before you start measuring out any of your other ingredients, add 1 tablespoon vinegar to a 3/4 cup measuring cup and fill the rest of the way with milk. Set aside to sour.
In a medium bowl, combine flour, brown sugar, baking powder, baking soda, spices, and salt. Whisk until well-combined.
In a small bowl, whisk together soured milk, pumpkin puree, egg, and vegetable oil.
Pour liquid into the flour mixture and use a spoon to stir until just combined. Do not over mix.
Heat a griddle to 350°F or skillet over medium heat and rub a stick of butter over the surface or grease with cooking spray. Drop heaping 1/3 cups of batter to the surface. If making in a skillet, you will need to make the pancakes in two batches.
Cook until bubbles form on the top of the pancakes and flip, making sure to cook all the way through—these pancakes will take slightly longer to cook than regular pancakes because of the pumpkin.
Top with butter and maple syrup, and enjoy!