Place mustard, parsley, garlic and butter into a medium size bowl and mix well until combined. Shape into a sausage shape and wrap in baking paper twisting the ends of the paper to seal. Refrigerate for 30 minutes
Season the eye fillet generously with salt and pepper and drizzle with olive oil. Heat a large heavy based pan on high heat. When hot add the fillet and sear until brown on all sides
Place beef onto a large heavy based baking tray and place into the oven for 15 minutes for medium rare (or longer depending on your cooking preference). Remove from the oven, add a few knobs of flavoured butter over the fillet and allow to melt while resting for 8 minutes before slicing into thick slices. Serve hot alongside extra butter
Tips & Hints:
Any remaining butter can be stored up to a week in the fridge.