The loin roast weight 2.5 lbs, but I diluted it with pineapple juice instead of water as I normally would and brined it for less than 1 hr per lb as I normally suggest, going for just 2 hrs. It could have gone longer but I wasn't familiar enough with the cut of meat or the kitchen I was to be cooking in to feel confident.
I pre-heated the oven to 450 F and got a stainless steel pan to medium high before I removed the lamb from the brine.
A little olive oil in the pan and the lamb loin went in whole as I browned all sides before placing it in the oven for 8-12 minutes, aiming for medium rare.
At home I would have reached for grape seed oil, which has a higher burning point, and I may not dilute the lime jalapeno fajita bath brine with pineapple juice in the future as the sugars burnt too quickly in the pan.