The Ultimate Grilled Chicken Sandwich

Ingredients

• Fried Onions
• Vegetable oil, as needed for frying
• 1 white onion, halved and thinly sliced
• 1 cup buttermilk
• 1 cup all-purpose flour
• 1 teaspoon smoked paprika
• ¾ teaspoon kosher salt
• ½ teaspoon freshly ground black pepper
• Dill Sauce
• 2 cups roughly chopped dill
• 1 cup Greek yogurt
• ½ cup buttermilk
• Zest and juice of 1 lemon
• 2 teaspoons onion powder
• Kosher salt and freshly ground black pepper
• Sandwich
• 4 large boneless, skinless chicken breasts
• 1 teaspoon mustard powder
• 3 tablespoons extra-virgin olive oil
• 8 thick slices seeded whole-grain bread
• 2 medium heirloom tomatoes, thickly sliced
• ½ cucumber, thinly sliced
• 1 cup parsley leaves