Season the beef fillet with salt and black pepper.
Sear the beef in a smoking hot frying pan with olive oil for 3 minutes until golden-brown.
Wrap the beef tightly in cling film to form a barrel shape and refrigerate for 1 hour.
Boil sugar, vinegar, salt, and 400ml of water in a pan.
Place beetroot in one pan and shallots in another, cover with the hot boiling liquor, and cool.
Pound salsa verde ingredients in a pestle and mortar until a thick paste forms.
Rub sourdough with garlic, drizzle with olive oil, and toast in a griddle pan until charred.
Slice the chilled beef thinly and arrange in a fan shape on a plate.
Garnish with salsa verde, drained pickles, leaves, onion, and a drizzle of olive oil.