Salvadoran Bean-and-Cheese Pupusas with Curtido

Prepare the vegetables by finely shredding 3 cups cabbage, coarsely grating 1/2 cup carrot, and thinly slicing 1/2 cup onion. Finely shred the mozzarella if needed.

Combine the cabbage, carrot, onion, sugar, oregano, and 3/4 teaspoon salt in a bowl. Massage firmly for 2 minutes until the cabbage begins to soften. Add the vinegar, toss well, and let the curtido stand for 25 minutes, tossing once halfway through.

In a second bowl, stir together the refried beans and mozzarella until evenly combined. Divide the filling into 8 equal portions, about 3 tablespoons each.

Combine the masa harina and remaining 3/4 teaspoon salt in a large bowl. Add the warm water and mix by hand for about 1 minute. Knead until smooth and pliable, with a texture like soft modeling clay, then rest the dough for 5 minutes under a damp kitchen towel.

Divide the dough into 8 equal pieces and roll each into a ball. Keep the portions covered while working so the masa does not dry out.

Hold one dough ball in a slightly damp hand and press your thumb into the center to form a deep cup. Add one portion of filling, pinch the dough completely closed, and gently roll it smooth. Pat between your palms into a 4-inch round about 1/4 inch thick. Repeat with the remaining dough and filling.

Heat a large skillet over medium heat for 3 minutes. Add 1 teaspoon vegetable oil and spread it into a thin film.

Cook the pupusas in three batches without crowding the skillet, adding 1 teaspoon oil before each batch. Cook for 3 to 4 minutes per side until the surfaces are browned in spots and the cheese filling is hot. Avoid pressing the pupusas as they cook.

Let the pupusas stand for 2 minutes before serving. Toss the curtido, lift it from excess dressing, and serve it generously alongside the warm pupusas.