In a bowl, mix the rosemary, garlic, salt, pepper and lemon zest together with the olive oil
Rub the seasoning onto the rack of lamb making sure to cover the whole rack and let it rest overnight in the fridge
Set sous vide bath to 134° Fahrenheit
Using the immersion method, place rack in a zip bag and immerse in water and let cook for 2 hours
When the rack has finished cooking, take it out of the bag and set aside
Preheat a nonstick frying pan on a high heat and add enough oil to thinly coat the surface
Add some thyme, rosemary, and garlic to the pan to flavor the oil
When the pan is hot, add the rack of lamb, fat side down and sear the fat until golden brown and crispy, about 1-2 minutes
Lower the heat and flip your lamb over to the meat side and cook for about 30 seconds then remove from the frying pan
Cover the lamb with foil and let it rest for 5 minutes before carving and serving
