Boil potatoes until they are fully cooked. Drain. Mash potatoes with the salt about 1 tablespoon of warm milk (do not add any butter or oil!) and let cool.

Grab a handful of mashed potatoes, split the handful in half, and make each half into a little bowl by pressing in with your fingers.

Stuff the indentation in each half with the spiced ground beef (recipe below) or picadillo (recipe here).

Bring the two halves together and smooth to make a round ball, about the size of an overstuffed golf ball.

Mix together the bread crumbs and the flour.

Dip the ball into the beaten egg, and then roll in the flour mixture until lightly covered. Dip the ball in the egg again and roll in the bread crumbs to coat thoroughly.

Important: Refrigerate the balls for two to four hours before proceeding to the next step. You may also freeze for later use, see "deep frying" note below.

Use a frying pan with enough oil to cover half the ball at a time. Heat oil to the frying stage (about 375º F) and drop each papa rellena into the hot oil. Let it cook for about two minutes or until golden brown. Turn the balls and cook the other half in the same way.

If you have a deep fat fryer, heat the oil to 375º F. place a single layer of papas rellenas in the basket, drop into the oil and cook for about 3 minutes, or until golden brown. Be careful not to overcook. Deep frying works best if the rellenas are frozen.