A lamb leg is classic. A 3-hour shoulder is excellent. But for the most succulent roast lamb of your life, slow-roast it for 12 hours in the oven overnight. Cooked at a very low temperature with plenty of braising liquid, you can set-and-forget without a worry. This entirely hands-off, easy cooking method yields superior results with the bonus that it reheats 100% perfectly and you can cook up to 4 shoulders at once.
Marinade/rub: Mix the Marinade ingredients in a small bowl. Rub all over the lamb surface, getting it right into all the cracks and crevices!
Marinate 2 – 24 hrs: If time permits, marinate for 2 hours on the counter in a roasting pan, or up to 24 hours in the fridge. I skip this step more often than not, however. (Note 4)
Prepare roasting pan: Scatter onion in the base of the roasting pan. Place lamb shoulder on top . Pour water into pan.
Roast uncovered for 45 minutes.
Slow-roast 12 hours: Turn oven down to 100°C/210°F (both fan and standard, Note 5). Cover lamb with baking paper, then a double layer of foil and seal very tightly to avoid water evaporation. Roast for 12 hours (I always do overnight!).
Check meat – Test side of lamb with two forks. The meat should be fall-apart tender. If not, cover and return to oven.
Remove lamb: There will (should!) be a lot of liquid pooled under the lamb in the roasting pan. Remove lamb to a large dish. Cover loosely with foil to keep warm. It will stay warm for 2 to 3 hours. See Note for reheating / making ahead.
LAMB JUS:
Reduce liquid: Strain all the liquid in the roasting pan into a saucepan (Note 2). Bring to a boil then simmer rapidly on medium-high until it reduces down to 1 cup (250ml).
Thicken: Mix cornflour with water. Pour into jus in a thin stream while stirring continuously. Continue to cook for a minute or two over medium heat, stirring every now and then, until it thickens to a syrup consistency. Add salt and pepper to taste.
SERVE:
Serve Slow Roasted Lamb with Jus. Use tongs for tearing meat off – no knife for carving needed! Pictured in post with Greek Lemon Roasted Potatoes, a perfect match for this Greek-ish flavoured lamb. Roasted Vegetables would also be ideal.