Grilled Pork Chops With Plum Mostarda

Name: Grilled Pork Chops With Plum Mostarda
Ingredients: 1 medium shallot, finely chopped; ¼ cup red wine vinegar; 2 Tbsp. whole grain mustard; 1 Tbsp. plus 1 tsp. granulated sugar; 2 tsp. Dijon mustard; ½ cup extra-virgin olive oil, plus more for grill; 2 tsp. finely chopped oregano; Kosher salt, freshly ground pepper; 4 large plums, halved, pitted; 2 1”-thick bone-in pork rib chops; 2 tsp. light brown sugar; ½ tsp. smoked paprika; 4 oz. mature arugula, tough stems removed (about 4 cups)