Add half the water and a pinch of salt in a mixing bowl, slowly add the masa harina as you churn the mixture with your hand or a mixing spoon.
Continue to churn the mixture and add more flour until it is all mixed in. The consistency of the mix should be soft but not too wet. To touch, the masa shouldn’t stick to your hands, but should leave an imprint.
Measure out the masa into approximately 25g balls.
Place the masa ball in between the two sheets of the plastic bag. Press inside a tortilla press or place on a strong flat surface and roll out to a thin circle. Carefully lift the top layer of plastic off and place the masa side down on your hand while again carefully peeling back the remaining plastic.
Put each flattened masa on a clean, pre-heated hotplate and cook until the surface is getting crisp, then flip and cook the other side.