3 to 4cups finely shredded Monterey Jack cheese
1 cup of Salvadoran cream (or substitute sour cream mixed with ¾ teaspoon salt)
4 cups instant corn masa flour
3½ to 4 cups water
½ cup water to wet hands
Preparing the Corn Masa Dough: Place the corn masa flour in a shallow bowl. Mix in the water, 1 cup at a time, kneading by hand for about 10 minutes until the dough is moist and fluffy. If needed, add more water 1 tablespoon at a time. The dough can be prepared the day before if covered and refrigerated.
Making the Pupusas:
Divide the dough into 12 equal small balls. Divide the filling equally for the 12 pupusas. Take the dough ball in the palm of your hand, pushing the center of the ball with your fingers to make a well. Fill each pupusa with the cheese filling. When done, close the top by pushing and pinching the open space together, so that the end result will be a completely filled and sealed dough ball. Wet your hands, press and pat each ball between your palms and flatten into a thin dough round that is about 4 inches in diameter and ¼-inch thick. Make sure the edges are nice and thin but be careful not to press too hard so that the filling does not spill out of the sides.
Cooking the Pupusas:
Heat a non-stick griddle or large heavy skillet over a medium to high flame. Gently place the pupusas on the hot surface and cook for about 5 minutes on each side, frequently turning them over to ensure even cooking. The pupusas are ready when they puff up and turn slightly golden.