01 -
Combine soy sauce, mustard, garlic, thyme, rosemary, and ginger in a bowl. Add olive oil bit by bit while stirring until it becomes creamy like mayo. Rub mixture all over the lamb. Let it rest on a rack in a roasting pan (fat side up) for 2 hours at room temp.
02 -
Heat oven to 425°F. Layer chunks of onion, lemon circles, and herb sprigs under the rack in your roasting pan.
03 -
Bake the lamb at 425°F for about 30 minutes.
04 -
Set oven to 350°F and continue cooking until the lamb’s internal temperature gets to 135°F for medium-rare or 145°F for medium (this takes about 1.5 hours). Pour 2 cups of chicken broth into the pan after an hour, and top it up after another 30 minutes if needed.
05 -
Pull the lamb from the oven just before it hits your target temperature (5°F lower). Put it on a chopping board, cover with foil loosely, and leave it alone for 20–30 minutes.
06 -
Strain and skim the fat from drippings in the roasting pan into a measuring cup. Add broth to reach a total of 2 cups. Stir together flour and water to make a paste. Place the pan over high heat, scrape it with wine, and let it reduce by half. Pour in juices, whisk in the flour mix a little at a time, and simmer until it thickens, about 5 to 10 minutes. Adjust seasoning with salt and pepper.
07 -
Cut away the string or netting from the lamb, slice it up, and pour on that delicious gravy.