Rub the lamb shoulder with salt and let it sit in the fridge, uncovered, overnight.
Heat a sous vide water bath to 132F degrees.
Place the lamb shoulder in a vacuum seal bag (or ziplock freezer bag if using the water displacement method) with all the remaining ingredients (except mint). Seal the bag.
Place the lamb in the water bath and cook for 24 hours.
Remove the shoulder from the bag, reserving the bag juice.
Heat a skillet over medium high heat and add 1 tablespoon of oil (any high smoke point oil like peanut, avocado, coconut, vegetable, etc.).
Sear the lamb shoulder on all sides for about 20-30 seconds per side.
Remove and slice. Serve drizzled with the reserved bag sauce and sprinkled with fresh mint. Perfect served with couscous.
Notes
Whether you use a vacuum seal or ziplock bag, you’ll want to make sure to properly remove the air from the bag so bacteria doesn’t get in.
If the bag starts to fill with air and float, just open the bag, remove the air and reseal it.
The bag should be fully submerged in the water bath. To help prevent floating, I like to weigh the bag down with something heavy or use a sous vide sinker weight.
Since it’s a long cook time, check on the water level. If it looks like it is evaporating, just add more water.
To get the best sear, use a high smoke point oil and pat the lamb dry with paper towels after it comes out of the water bath.
When reverse searing the lamb, be careful not to sear it for too long. If it’s seared for longer than 20-30 seconds per side, it may overcook and dry out.
Before slicing the lamb, let it rest for 10 minutes so the juices have time to redistribute throughout the roast.
When slicing the lamb, be sure to cut against the grain. If you cut with the grain, the lamb will be tough and chewy to eat.