Instructions

1. Pre-heat oven to 200-220°C
2. Season both sides of the fillet with salt and cracked black pepper.
3. Add the butter and oil to a cast iron pan and heat to medium-high heat.
4. Add the fillet to the pan and sear each side until beautifully browned – about 2-3 minutes per side. 
5. Add the garlic and rosemary to the pan and then tilt the pan to one side, so that all the butter gathers and then spoon the butter over the fillet for a minute or so.
6. Now, place the pan in the pre-heated oven and cook as follows: 10-15 minutes rare // 20 mins medium rare // 25 mins well done
7. Once cooked to your liking, remove from the oven, place the fillet on a cutting board and allow the fillet to rest for 5-10 minutes before cutting. This allows the juices which have all been driven to the centre of the fillet, to re-distribute so that when you cut the meat, its all very juicy!
8. Before cutting, either roll the fillet in the herbs or alternatively, use your hands to press the herbs onto the fillet (this is what I did)
9. Slice in medallions and serve with a horseradish sauce, roast potatoes and veggies of course!