In a large bowl, combine the masa harina with the salt; blend well.

Gradually add the hot water and melted butter, lard, or oil and mix with your hands until well combined.

Remove the dough to a lightly floured surface and knead for about 2 minutes, or until smooth.

Wrap the dough in plastic wrap and let it rest for 30 minutes to 1 hour.

Tear off 1 piece of dough (about 1 1/2 ounces). Shape the piece of dough into a ball and dust very lightly with flour. This will be your test tortilla.

Cut a food storage bag to make two sheets of plastic.

Place one sheet of the storage bag on the tortilla press. Place the dough ball on the plastic and then top it with another sheet of plastic. Press to flatten the tortilla. Carefully remove th tortilla to a floured towel. If it sticks to the plastic, the dough is too wet.

If necessary, knead a little more corn flour into your dough. Divide the remaining dough into 1 1/2-ounce pieces and shape them into balls.

Press each ball of dough.

Meanwhile, heat an iron or nonstick pan over medium heat.

When the pan is hot (a drop of water should sizzle and quickly evaporate), add a tortilla. Cook on one side for about 45 to 55 seconds, or until there are some light brown spots on the bottom. Flip and cook for another 45 to 55 seconds. Flip one more time and press the tortilla with the spatula. It will puff up. Remove it to a towel and keep warm if you will be eating immediately.

Repeat with the remaining tortillas.