Remove your lamb neck fillets from the fridge and allow them 20 minutes to reach room temperature. Meanwhile preheat the oven to 180ºC.
Generously season the lamb with salt and pepper while bringing a large frying pan to a high heat. Add a drop of oil to ensure your pan doesn’t stick and add cook your fillets for around 2 minutes each side or until evenly browned.
Add the butter, rosemary and garlic to the pan, allowing it to foam and turn golden. Baste with the spoon for a minute or so, ensuring all sides of the fillet are attended to. Now transfer to the oven and cook for 8-10 minutes for medium rare.
Remove and allow to rest for 5 minutes before slicing into meaty little sections. Serve alongside seasonal vegetables and your choice of potatoes.