Honey-Vinegar Leg Of Lamb With Fennel And Carrots

Pulse garlic, parsley, fennel seeds, and 1/2 cup fennel fronds in a food processor until very finely chopped. With motor running, slowly add 1/4 cup oil and process until smooth; season generously with salt and pepper (mixture should taste quite salty as this is the only seasoning meat will get). Rub parsley mixture all over lamb. Transfer to a roasting pan, cover, and chill at least 8 hours.

Let lamb sit at room temperature 1 hour. Bring vinegar and honey to a boil in a small saucepan. Reduce heat and simmer, stirring occasionally, until slightly thickened, 8-10 minutes. Set glaze aside.

Place racks in lower third and middle of oven and preheat to 325u00b0F. Toss fennel and carrots with remaining 1/4 cup oil in a medium bowl and arrange half around lamb in roasting pan; place remaining vegetables on a rimmed baking sheet.

Roast vegetables on baking sheet on lower rack and lamb on middle rack until an instant-read thermometer inserted into the thickest part of lamb registers 100u00b0F, about 1 hour.

Increase oven to 450u00b0F, brush roast with glaze, and continue to roast until an instant-read thermometer registers 120u00b0F, 20-25 minutes longer. Transfer lamb to a cutting board and let rest 30 minutes before carving (temperature will rise to 140u00b0F for medium-rare while lamb is resting).

Continue to roast vegetables, tossing occasionally, until golden and tender, 20-25 minutes longer.

Serve lamb with vegetables, topped with fennel fronds.

DO AHEAD: