Thoroughly rinse produce and pat dry. Keep prosciutto in refrigerator until use.
Core tomato and cut into ½" rounds.
Place prosciutto on a plate and microwave until crisp, 2-3 minutes.
Toast roll until lightly toasted, 2-3 minutes.
In a bowl, combine mustard, mayonnaise, and apricot preserves.
Top bottom bun with prosciutto, then cheese, sliced tomatoes, arugula, apricot sauce, and top bun. Bon appétit!