Slice the chicken breasts horizontally into 4–6 thin cutlets. In one bowl, whisk the egg with milk, garlic powder, salt, and pepper. In another bowl, combine breadcrumbs and Panko. Dip each cutlet into the egg mixture, then coat in the breadcrumb mixture. Fry in about 1 inch of oil over medium-high heat for about 5 minutes, or until golden brown and crispy. Transfer to a paper towel-lined plate.

In a small bowl, mix together melted butter, mayonnaise, minced garlic, parsley, and Parmesan to make the garlic butter. Split the bread lengthwise and spread the mixture evenly on the inside. Toast in a 450°F oven or under a broiler for 3–4 minutes until golden.

Whisk together all dressing ingredients until smooth. In a large bowl, toss chopped romaine with 3–4 tablespoons of dressing until lightly coated.

To assemble, layer crispy chicken cutlets onto the toasted bread, top with Caesar salad, and finish with extra grated Parmesan. Serve immediately.