Mix 2 cups of shredded cabbage and 1 cup of grated carrots in a large bowl. In a separate bowl, combine 1 cup of hot water, ½ cup of white vinegar, 1 tablespoon of sugar, and 1 teaspoon of kosher salt, stirring until dissolved. Pour the brine over the cabbage mixture and let it pickle for at least 4 hours, preferably overnight.

In a large mixing bowl, whisk together 2 cups of masa harina and 1 teaspoon of kosher salt. Gradually add 1 ¼ cups of cold water, mixing until a soft, pliable dough forms. Divide into 8 equal balls and cover with a damp cloth.

Flatten a dough ball to form a disk, add a mixture of ½ cup of shredded cheese, pickled jalapeños, and ½ cup of roasted butternut squash in the center. Fold edges over and pinch to seal. Flatten again to ensure the filling is enclosed.

Heat a cast-iron skillet over medium heat and add 1 tablespoon of oil. Cook pupusas for 4-6 minutes on each side until golden brown and crispy. Keep warm in the oven while cooking the remaining pupusas.

Serve warm pupusas alongside curtido, lime wedges, and salsa for dipping. Enjoy the combination of flavors and share with friends and family.