Slice the chicken breasts horizontally to create four thin cutlets. Set up a breading station with flour, beaten eggs, and panko breadcrumbs. Dip each chicken cutlet in flour, shake off excess, coat in egg, then panko.

Heat olive oil in a skillet over medium heat. Add breaded chicken cutlets, fry for about 4 minutes per side until golden brown and crispy. Transfer to paper towels to drain.

In a blender or food processor, combine garlic, jarred roasted bell peppers, sun-dried tomatoes, almonds, balsamic vinegar, olive oil, paprika, and kosher salt. Blend until smooth.

In a mixing bowl, combine sour cream, mayonnaise, lemon juice, grated Parmesan, and black pepper. Fold in chopped gem lettuce and arugula.

Mix softened butter with minced garlic and parsley. Slice focaccia in half horizontally and spread garlic butter on both sides.

Preheat grill or grill pan over medium heat. Place focaccia, butter side down, on the grill, cooking for about 3–4 minutes until golden.

Spread romesco sauce on grilled focaccia halves, layer crispy chicken cutlets on top, followed by the salad mixture. Close sandwich and press gently.

Wrap each sandwich in parchment paper. Serve immediately for best crunch or store in the fridge.