Step 1

Warm up the mashed potatoes and place them in a medium mixing bowl with the flour, baking powder, salt, and melted butter.  Measure out the milk and set it aside.

Step 2

Working quickly so the potatoes don't turn pink, peel and grate the two potatoes.  Squeeze as much liquid as possible out of the grated potato with paper towel, then stir it into the flour mixture.

Step 3

Gradually mix in the milk until all the flour is picked up from the bowl and a sticky dough has formed.  Turn out the dough onto a lightly floured surface and gently knead a few times until the mixture is well combined.

Step 4

Shape the dough into a disc and place on a lightly floured baking stone or a parchment-lined cookie sheet.  Score in a cross shape with a sharp knife, cutting almost all the way through the dough.

Step 5

Let the boxty rest for about 10 minutes on the counter while the oven is preheating to 400 F.

Step 6

Bake at 400°F for about 40 minutes, until the loaf is a lovely golden brown.  Let the bread cool a little on a wire rack before serving.  It tastes best warm and spread with butter.