Make the masa

1. Add the masa harina to a medium bowl. Pour in 1½ cups / 360 ml of the warm water and mix with your hand until no dry patches remain.
2. Knead in the bowl for 2 to 3 minutes, until the dough is smooth and cohesive. It should feel soft and springy. If it cracks when you squeeze a small piece, knead in a little more water. If it sticks heavily to your palm, knead in a little more masa harina.
3. Cover with a towel and let the dough rest for 20 minutes so the masa harina can fully hydrate.

Portion and shape

1. Set a dry cast-iron skillet or comal over medium-high heat so it gets fully hot while you shape the tortillas.
2. Divide the dough into 12 equal pieces and roll them into smooth balls.
3. Line the tortilla press with plastic. Press one ball into a round about 5 to 6 inches / 13 to 15 cm wide and about 1⁄16 inch / 2 mm thick. If the edges split a lot, the dough is still too dry.

Cook and keep warm

1. Peel the tortilla from the plastic and place it on the hot dry skillet. Cook the first side for 30 seconds, or until the surface looks more matte and the tortilla releases easily.
2. Flip and cook the second side for 30 to 45 seconds, until light brown freckles appear.
3. Flip once more and cook 15 to 30 seconds longer, until the tortilla puffs in spots or fully balloons. Success looks like a warm corn aroma, a dry-looking surface instead of a wet sheen, and a center that bends easily with no raw or gummy feel.
4. Transfer to a towel or tortilla warmer and keep covered while you cook the rest. The trapped steam keeps them soft and pliable for serving.