In a heatproof bowl, mix the salt and flour together.

Now, with your fingertips, work the shortening into the flour until you have a crumbly-looking mixture.

Add about 3/4 of a cup of boiling water and try to stir it into a dough. Add a bit more boiling water, if needed, until it all comes together in a ball.

Turn the dough out on the counter and knead for about 5 minutes, until it becomes smooth and elastic.

Wrap the dough in plastic wrap and let rest at room temperature for at least 30 minutes.

Put a griddle or cast-iron skillet to heat over medium heat.

Divide the dough into four roughly equal pieces, and, on a lightly floured surface, roll out to about 8-inch circles.

Put the rolled-out tortilla on the griddle and cook for about 1 minute per side, or until golden brown spots form.

As each tortilla comes of the griddle, place it under a clean dish towel to keep warm.