Combine the mashed and raw potatoes in a mixing bowl. Mix well to combine.
In a second bowl combine the flour, baking powder, baking soda, and salt.
Add the flour mixture to the potatoes and mix to combine.
Stir in the buttermilk. Add additional milk 1 tablespoon at a time if batter seems too thick. Keep in mind this batter should be thicker than most pancake batters.
Heat your griddle up to it's highest temperature.
Using a ladle to drop the batter onto the griddle. Cook for about 4 minutes per side until brown.
You can place them in a oven set to it's lowest temperature to keep them warm.