How to Make It
Heat oven to 400° F. In a small bowl, toss the bread crumbs with 1 tablespoon of the oil; set aside.
Heat 1 tablespoon of the remaining oil in a large skillet over medium-high heat. Season the pork with ½ teaspoon each salt and black pepper and brown on all sides, 6 to 8 minutes.
Transfer the pork to a rimmed baking sheet; reserve the skillet. Coat the pork with the mustard, then pat on the bread crumb mixture. Roast until the internal temperature registers 145° F, 40 to 45 minutes (tent with foil if the bread crumbs become too dark). Let rest 5 minutes before slicing.
Meanwhile, to the reserved skillet, add the remaining 2 tablespoons of oil, the cauliflower, and ¼ teaspoon each salt and black pepper. Cook, tossing occasionally, until tender, 10 to 12 minutes. Add the cherry peppers, capers, and parsley and toss to combine. Serve with the pork.