Southern Fried Chicken BLT

Name: Southern Fried Chicken BLT
Ingredients: 2 Tablespoons mayonnaise; 1 Teaspoon Dijon mustard; 1/8 Teaspoon sea salt; 1/8 Teaspoon freshly ground black pepper; 1 Teaspoon stone-ground mustard; Two 6-ounce boneless, skinless chicken breasts; 2 Cups buttermilk; 4 slices bacon; 2 Cups canola oil; 1 Cup all-purpose flour; 2 Tablespoons cornstarch; 3/4 Teaspoons sea salt; 1/2 Teaspoon freshly ground black pepper; 2 artisan hoagie rolls; 2 Teaspoons unsalted butter; Romaine lettuce, to taste; 1 red ripe tomato, sliced