Add vinegar to milk, stir and set aside. In a bowl, beat the eggs, and gradually beat in the melted butter. Then add milk, pumpkin and vinegar to the egg mixture. Combine the flour, brown sugar, baking powder, baking soda, allspice, cinnamon, ginger and salt in a separate bowl. Stir into the pumpkin mixture just enough to combine.
Heat a lightly oiled griddle or frying pan over medium high heat. Pour or scoop the batter onto the griddle, using approximately 1/4 cup for each pancake. Brown on both sides and serve hot.