Make sure all the potatoes are cut into equal size pieces so that they all cook at the same time. Place the potatoes into a large pot and fill it with cold water, enough to fully cover the potatoes. Add about 1 tsp of salt to the water and stir.
Bring the potatoes to a boil over high heat, then reduce the heat to a medium and cook for about 15 minutes or until the potatoes are fork tender.
Drain the potatoes. Put the potatoes through a potato ricer, press them through a sieve or simply use a potato masher to get them as fluffy as possible.
To the mashed potatoes add the flour, 3 tablespoons of butter, salt and pepper and mix thoroughly until you form a dough.
Flatten the dough into an 8-inch disk on a lightly floured surface, about 1-inch thick then cut into 8 triangles, like cutting a pizza.
Melt remaining 3 tablespoons of butter in a large skillet. Add the potato cakes and cook for about 4 to 5 minutes per side, over medium heat, until gold and crispy.
