Step 1

In a large bowl, combine the cabbage, onion, and carrot and mix until thoroughly combined. Set aside.

Step 2

In a second large bowl, combine the salt, oregano, and red pepper flakes. Stir in the water and apple cider vinegar.

Step 3

Pour the spiced vinegar mixture over the vegetables and knead until the vegetables have softened, about 5 minutes. Let sit for 10 minutes at room temperature before serving.

Step 4

Store the curtido in an airtight container in the refrigerator for up to 1 month.

Step 5

In a blender on high speed, blend the cooked beans and broth until smooth. Set aside. In a large frying pan over medium heat, warm the grapeseed oil until it shimmers. Pour the blended beans into the pan and bring to a boil; keep them on medium heat and constantly stir until they reach a stiff texture and no liquid remains, about 25 minutes. Remove from the heat and let cool completely.

Step 6

Transfer the beans to a large bowl. Add the quesillo and mash the cheese into the beans so that no large chunks remain. The mixture should be thoroughly combined and have a uniform color, with no parts too cheesy or too concentrated with beans. Set aside.

Step 7

In another large bowl, combine the masa harina and water and knead until it reaches the consistency of Play-Doh. (You may choose to do this in batches. Divide the water and the masa harina and mix one batch at a time.) When the dough is pressed, its sides should not tear.

Step 8

Pour some water into a small bowl and keep it handy for moistening the dough. Roll about 3 ounces of masa (slightly larger than a golf ball) between the palms of your hands until it forms a completely round ball. Then start flattening it with the fingertips of your dominant hand. Rotate the round slightly so that it gets pressed down evenly. Once the round is about 5 inches in diameter, cup your hand so that the pressed-out dough is now a pocket. Put about 3 ounces of filling into the pocket and press the filling tightly inside. Fold the edges of the dough toward the center to seal the pupusa, and twist off any remaining dough. This should form a filled disk. Using your dominant hand, pat and flatten the disk until it is 6 to 7 inches in diameter. (If the dough cracks at any point, it needs more moisture; add more water and mix into the dough until it becomes elastic again.)

Step 9

Set a comal or griddle over medium-high heat. When the comal is hot, add the pupusas and cook until they puff up and the exteriors have browned, about 5 minutes per side. Transfer the pupusas to a plate and cover with a kitchen towel to keep them warm. Repeat the process until you run out of masa and filling.

Step 10

Serve the pupusas immediately with curtido and salsa roja. ¡Provecho!