Remove the lamb from your fridge and allow it to reach room temperature, this is crucial for even cooking. Cooking lamb straight from the fridge can result in the outside of your lamb overcooking and becoming dry.
Place the lamb in a heavy based roasting tray. I like to slice some potatoes approximately 1cm thick and place under the lamb, this helps prevent the base drying out and gives you some amazing tasting potatoes. I recommend investing in a good, solid roasting tray for the best results. Thin trays can cause meat to burn and may buckle in the oven.
Drizzle the lamb with vegetable oil and season with salt and cracked black pepper. I stud my lamb with sprigs of rosemary and whole peeled garlic cloves. Halfway through cooking, I brush the lamb with Dijon mustard and cover with a lemon, garlic and rosemary herb crust.
Cook at 180 degrees for 30 minutes then another 25 minutes per 500 grams. Use a probe to identify the core temperature.
Once cooked, remove from the oven, cover with foil and rest for 20 to 30 minutes before carving. The foil keeps your lamb warm, juicy and succulent.
The most important 3 factors when roasting for perfect results are:
Don’t throw away those lovely meat juices. Drain off excess oil, place the tray on top of the stove, heat and add lamb stock. If you have made your gravy separately, add the gravy to the pan incorporating all the sticky juices by rubbing the base of the tray vigorously with a spatula (if you have done this properly, your tray will be clean when you tip your gravy in to your jug). Add a sprig of rosemary or thyme if you want a little extra flavour, adding a spoon of redcurrant jelly gives you a little sweetness to your gravy.
To produce a jus, deglaze your tray using white wine, add lamb stock and thicken with a little cornflour.