Step 1: Prepare the Mashed Potatoes. If you don't have leftover mashed potatoes, boil about 2-3 medium potatoes until tender, then mash them with a fork or potato masher. Allow them to cool slightly.
Step 2: Combine Ingredients. In a mixing bowl, combine the mashed potatoes, flour, baking powder, and salt. Mix until just combined to avoid overworking the dough.
Step 3: Form the Cakes. Dust your work surface with extra flour. Turn the dough out and knead gently. Roll out to ½ inch thick and cut out circles.
Step 4: Cook the Cakes. Heat a skillet over medium heat with a little oil or butter. Cook the cakes for 3-4 minutes on each side until golden brown.
Step 5: Serve and Enjoy. Remove from skillet, cool slightly on a wire rack, and serve warm with your favorite toppings.