Mix 100g butter with parsley and chives in a bowl.
Roll the butter into a log using film and chill for one hour.
Butterfly chicken breasts and flatten them with your palm.
Blend peanuts to a powder and mix with panko breadcrumbs.
Dredge chicken in seasoned flour, dip in egg, and coat with peanut crumbs.
Fry chicken in butter and oil for 3 minutes per side until golden.
Boil potatoes for 15 minutes or until tender.
Drain potatoes and heat briefly to remove excess moisture.
Process potatoes through a ricer or mash well.
Heat milk and 110g butter, then beat into the potatoes and season.
Wilt spinach in 50g foaming butter and season with salt, pepper, and nutmeg.
Serve mash and spinach topped with chicken and slices of herb butter.