So you know me, after seeing how pupusas were made in person at the Farmers' Market in Alhambra, I had to give it a shot myself. They ended up being super easy to make.
I just used the tortilla recipe on the side of my bag of masa harina.
Pupusas with Beans and Cheese
For about 4 to 6 palm-sized pupusas, you'll need:
2 cups masa harina (corn flour, not corn meal)
1 to 1 1/4 cup water
Mix 1 cup water with 2 cups masa harina until a slightly wet lump of dough is formed. The dough should not "crack" when you press down on it. Add more water, starting with 1 tblsp at a time, until you get the right consistency.
In the first method, flatten the lump of dough back and forth in your hands until two equal-sized discs are formed. You may use a rolling pin if you want the dough thinner.
Pile a spoonful of beans and some shredded cheese on one of the discs. I had leftover refried beans from a Mexican lunch.
Top the other disc over the mixture and smooth the edges.