In a small bowl, combine the milk and apple cider vinegar. Let sit for 5 minutes to create buttermilk.
In a large bowl, whisk together the flour, baking powder, salt, and brown sugar.
Add the mashed sweet potato, eggs, and melted butter to the buttermilk mixture and whisk until well combined.
Pour the wet ingredients into the dry ingredients and gently fold until just combined. Be careful not to overmix.
Heat a non-stick skillet or griddle over medium heat and lightly grease with butter or oil.
Pour 1/4 cup of batter onto the skillet for each pancake. Cook until bubbles form on the surface and edges look set, about 2-3 minutes.
Flip and cook for another 2 minutes until golden brown and cooked through.
Serve warm with your favorite toppings such as maple syrup, fresh fruit, or nuts.
