Pupusas are “tortillas” made of corn dough, with a filling of cheese, “chicharron”, fried beans or mixed fried beans and chicharron.  
Recipe for Pupusas:
To prepare the dough, purchase a package of MASA HARINA (you will see the label, there are several brands, but if it reads “Masa para tortillas”, that is the right one). On the package you will find the instructions of how to make the dough.  Be careful with the water you add to the flour, too much is not good, too little will feel hard. The dough ought to be malleable. Once the dough is ready, cover with a clean, moist dish cloth and set aside.

Next prepare your filling of choice:

Pupusas de Queso: Purchase fresh cheese and hard cheese. Grate it, and make three cups. It ought to be a very fine grating. Add 4 tablespoon of real cream (not sour cream). If you live near a store where you find LOROCOS try half to one cup of Lorocos. Add a little salt to your taste. Make a paste of all of this, making sure the paste is NOT liquid. It should not be runny. Set this mixture aside.

Pupusas de Chicharron: Purchase in a Latin market 1.5 cups of chicharrones (do not confuse these chicharrones with the mexican chicharron). Also get the following
  • ½ cup of water
  • 4 tomatoes
  • 1 clove of garlic
  • 1 green pepper
  • one onion
  • salt to your taste
Fry the chicharrones in its own grease. Once fried, put it into the blender together with four or five medium tomatoes, the green pepper and the onion. If you would rather not fry the chicharrones then do the following.  Bring 3 cups of water to a boil, add the chicharrones and let them sit in the boiling water for about 10 minutes. Now peel the tomatoes removing the seeds, in a way that you have just the pulp. Remove the chicharrones and let them cool. When the chicharrones are cooled, put them in the blender with the tomatoes and salt to your tastse.  You will have 2 cups of chicharrones. If you wish, you can add to the mixture the grease from the chicharrones- this way the pupusas won't be so hard. To make Revueltas (beans and chicharrones), fry some beans with garlic and onion. You can mash the beans if you wish, and you can use beans from a can. Add the beans to the chicharrones mixture.

Now finish making the pupusas:

From the dough you set aside, take about three big spoonfuls of it and make a little ball. Flatten this ball with your hands and begin making it round. Once it is round pat it flat. Now, put this flattened ball over a cloth on the counter and put your filling of choice on top. Make the lid by making another little ball, flatten it, round it. Cover the first one that has the filling. Touch the edges so the filling won't go out. The griddle should be very hot (350). Cook each side until it is golden brown but not burnt.

Good Luck!