Lamb from new-fangled Joy recipe

I reworked my lamb recipe for Christmas Eve 2018 in the Madison kitchen.  I wanted to avoid the two-shift oven treatment.  This recipe is a blend of the "new" JOY (which has no coating, not even breadcrumbs) and my old one:

Mash 1 clove garlic with 1/2 tsp salt.  Mash in 1/2 t. dried thyme, then beat in 2 - 3 T. dijon mustard and 3-4 T. olive oil.  Whisk together.

Pre heat oven to 400 (same as for Yorkshire pudding, but Joy calls for 425). Have skillet on med hi with 3 T butter, hot. Brown on 3 sides, 2 min each. Coat top and sides with mustard mixture and put in oven, maybe 20 min. 15 min (rare) to 21 (med. well) minutes. Rare is 125 degrees.  Wait a few minutes, loosely covered with foil, before carving.

The Yorkshire pudding went into the 400 degree oven before I browned the lamb and did ok at that temp for the 30 min that the lamb needed.  Before I started any of that, I'd slow-cooked sweet onions, first on hi, then low, and added brussel sprouts.