4 tbsp all-purpose flour
1 bunch rosemary, some leaves stripped and chopped
600 ml | 21 fl oz | 2 1/2 cups milk
100 ml | 3 1/2 fl oz | 7 tbsp lamb broth, or chicken broth
100 ml | 3 1/2 fl oz | 7 tbsp heavy cream
2 New Zealand Spring Lamb Loin fillets, 9 oz each, trimmed of silver skin
2 tbsp olive oil
2 garlic cloves, crushed
- Preheat oven to 200°C (180° fan) | 400 F | gas 6.
- Melt butter in a heavy-based saucepan set over a medium heat. Once melted, whisk in flour and cook until roux is golden in appearance, 2-3 minutes. Whisk in about 1 tbsp chopped rosemary.
- Gradually whisk in milk followed by broth. Bring sauce to a simmer and cook steadily for 5-7 minutes until thickened.
- Whisk in cream and return to a simmer. Season to taste with salt and pepper, cover, and set aside until needed.
- Season lamb fillets with plenty of salt and pepper. Heat olive oil in a heatproof pan set over a moderate heat until hot.
- Sear lamb in the pan until golden all over, making sure to sear the ends of the fillets. Add the remaining rosemary to the pan as well as the garlic.
- Transfer to oven and roast for 6-10 minutes until the thickest part of fillets registers at least 63°C | 145F on a meat thermometer.
- Remove from oven and transfer fillets to a plate, covering with aluminum foil and letting rest for at least 10 minutes. In the meantime, gently reheat rosemary sauce.
- After resting, cut lamb into thin slices. Ladle sauce into bowls and present lamb on top before serving.