Polenta Dutch Baby with Ham and Swiss

Name: Polenta Dutch Baby with Ham and Swiss
Ingredients: 1/2 cup all-purpose flour (about 2 1/8 ounces); 3 tablespoons granulated sugar; 2 tablespoons uncooked polenta (such as Bob’s Red Mill); 7/8 teaspoon kosher salt, divided; 1/2 cup whole milk; 3 large eggs; 3 tablespoons unsalted butter, cut into 3 pieces; 1 ounce thinly sliced deli ham, patted dry and cut into 2- x 1/2-inch strips; 1 ounce Swiss cheese, grated (about 1/4 cup); 1 teaspoon country Dijon mustard; 1 teaspoon Champagne vinegar; 1/4 teaspoon pure maple syrup or honey; 1 tablespoon grapeseed oil; 1 ounce baby arugula (about 1 cup); 1 ounce red grapes, quartered (about 1/4 cup)