Pour ¼ cup of oil into a small bowl and set aside. You'll use this to prevent the dough from sticking to your hands; the oil will also help hydrate the dough as you assemble it. Combine the chicken bouillon and warm water; set aside. In a large mixing bowl, combine the masa harina, melted butter, and enough water to incorporate the Masa (up to 4 cups).

Knead together inside the bowl by pressing the heels of your hands into the dough, pushing forward slightly. Continue to knead until you have a moist dough that releases from the bowl and does not stick to your hands; if the mixture is too dry, add more warm water, one tablespoon at a time. If the mixture is too sticky, add more Masa Harina, one tablespoon at a time.

The dough will be very tacky and stick to your hands; as you keep kneading, the dough will become softer and won't stick, and that's when you know your dough is ready. Covered with a damp towel and let it rest for 10 to 15 minutes.

Divide into equal balls of approximately 50g. Roll each piece into a ball, then place the balls on a baking sheet, and cover with a damp clean kitchen towel to keep the dough moist and soft; set aside.

Place a piece of parchment paper or thick plastic wrap (from a 1-quart zip-lock bag) onto a tortilla press. Place one of the balls in the center of the press. Top with another piece of parchment paper, close the press, and push the lever down to form a 6-inch round tortilla. (Alternately, the dough balls can be rolled between plastic sheets with a rolling pin.)

Open the press and remove the top layer of plastic. Carefully peel the Corn Tortilla off the bottom plastic and place it onto a hot, ungreased cast-iron skillet; cook on medium-high for about 30 seconds on each side, turning 3 times. (Careful not to overcook the tortilla).

Remove the tortilla and place it on a clean tea towel; keep it covered to keep it soft and pliable. Continue until you have used up all the dough. Enjoy!