CUBAN SANDWICH WITH ZUCCHINI PICKLES

Steps:

• ZUCCHINI PICKLES
• Bring vinegar, sugar, turmeric, mustard powder, and mustard seeds to a boil in a medium saucepan, stirring to dissolve sugar. Let cool. Toss zucchini, onion, and salt in a large bowl and let stand until zucchini releases moisture, 30-35 minutes. Pat zucchini and onion dry and transfer to a large jar. Pour pickling liquid over vegetables to submerge. Cover and chill at least 12 hours.
• DO AHEAD: Zucchini can be pickled 4 days ahead. Keep chilled.
• SHREDDED PORK AND ASSEMBLY
• Preheat oven to 300°. Combine onion, carrot, celery, oregano, rosemary, red pepper flakes, and broth in a Dutch oven or other large pot. Place pork on top of vegetables and drizzle with oil; season pork with salt and pepper. Cover and braise, turning pork occasionally, until pork is just falling apart, 3½-4 hours. Let cool. Transfer pork to a large bowl, reserving 1 cup cooking liquid, and shred with a fork. Add cooking liquid as needed to moisten pork (you may not use all of it).
• Meanwhile, increase oven temperature to 400°. Mix mayonnaise and mustard in a small bowl and set aside. Place both halves of buns, cut side up, on a rimmed baking sheet. Layer soppressata, pork, and cheese on bottom halves of buns and bake until cheese is melted, about 5 minutes. Top bottom halves of buns with pickles; spread top halves of buns with reserved mayonnaise mixture and form sandwiches.
• DO AHEAD: Pork can be braised and shredded 3 days ahead. Cover and chill. Bring to room temperature before using.