Breaded chicken: Slice your chicken breast into 2 pieces length-wise. While working with 1 piece at a time, cover the chicken with a piece of plastic wrap and using a meat tenderiser, flatten out the chicken into a thin even piece. Repeat with the other piece. Season the chicken with salt and pepp.
Add your breadcrumbs onto a plate and mix in the parsley, onion powder and garlic powder. Prepare your breading station. Working with 1 piece of chicken at a time, place the chicken into your flour and cover it well. Transfer the chicken to your beaten eggs and cover it well. Transfer the chicken to your seasoned breadcrumbs and press it in well. Repeat with the 2nd piece.
Bring a pot of oil to frying temperature (180C/ 350F). Carefully drop in 1 piece of breaded chicken at a time and fry for 4-6 minutes, depending on the thickness of the chicken and flipping halfway, or until golden brown. Place on a wire rack to drain.
Grilled Cheese: Slice your loaves of bread in half, lengthwise and add in the mozzarella and cheddar cheese in-between the slices. In a pan over low-medium heat, add in your sandwiches and let the bread crisp up while the cheese melts (low and slow is key to allow the cheese time to melt). Flip the sandwich and let it toast on the other side.
Assemble: Working with 1 sandwich at a time, open your grilled cheese. Spread a generous layer of pesto, then top with a fillet of crumbed chicken, burrata, toasted hazelnuts, rocket and close the sandwich. Repeat with the second sandwich.