For an accurate measurement of boiling water, bring a full kettle of water to a boil and then measure out the desired amount. Properly hydrated masa dough should be tacky, requiring damp hands to keep it from sticking to your palms. If the dough feels the slightest bit dry at any time, knead in warm tap water, 1 teaspoon at a time, until the dough is tacky. An occasional leak while frying the pupusas is to be expected, and the browned cheese is delicious. Feta cheese can be substituted for the cotija; if you can find quesillo, use 10 ounces in place of the cotija and Monterey Jack.
Jen is a web producer at KPBS, responsible for program promotion, online membership-related activities, and is the editor of the KPBS community calendar. Jen has worked at KPBS since 2000. She is originally from Las Vegas and attended UNLV.