Apple and Cheddar Belong Together — In Your Next Sandwich

Name: Apple and Cheddar Belong Together — In Your Next Sandwich
Ingredients: 1/2 cup apple cider vinegar; 1/4 cup extra-virgin olive oil; 2 tablespoons honey; 4 teaspoons whole-grain mustard; 1/2 teaspoon black pepper; 1/2 teaspoon kosher salt; 2 small shallots , thinly sliced (about 1/3 cup); 2 small garlic cloves , grated (about 1/2 teaspoon); 1 tart green apple (such as Granny Smith) (unpeeled), cored and very thinly sliced crosswise; 1 tart-sweet apple (such as Honeycrisp) (unpeeled), cored and very thinly sliced crosswise; Salted butter , at room temperature; 8 slices soft multigrain sandwich bread; 4 to 8 ounces aged white cheddar cheese , thinly sliced; 1 1/3 cups packed baby arugula