Start by making the garlic and herb butter. Mix together the butter, garlic, finely chopped herbs, lemon juice and a little salt and pepper. Place the butter on cling film and roll into two equal log shapes. Make sure it is wrapped well. Place in the freezer whilst you prepare the chicken.
Place the chicken breasts in between two pieces of cling film. Bash with a meat tenderiser or a rolling pin until the chicken breasts are almost double the size they were and evenly thin. Season with a little salt and black pepper.
Remove the cooled butter logs from the freezer and place a log into each chicken breast. Wrap the chicken breasts around the butter logs tightly, trying to not leave any gaps. Wrap each chicken breast well in cling film and place each in the freezer for 30 minutes to firm up.
Lay out three plates. Put a handful of flour into one plate, the beaten egg in the next and a good handful of panko breadcrumbs in the third. Season the breadcrumbs with the onion salt, garlic powder and smoked paprika, if using.
Once the chicken has chilled, remove the cling film. Dip each in the flour, then the egg and then the breadcrumbs. Dip back in the egg and back in the breadcrumbs a few times until well coated, making sure there are no gaps.
Heat the oven to 200C. In a large saute pan, pour around 1-2 inches of sunflower oil so that it would come half way up the chicken kievs. Heat to 180C. Put each chicken kiev in the hot oil and fry for a couple minutes on each side until golden brown. Remove from the oil carefully and put into a baking tray. Cook for 20-25 minutes depending on the size of your chicken breasts until cooked through. Allow the chicken kievs to rest for 5-8 minutes before serving.