Grilled Lamb Loin with Cabernet-Mint Sauce and Garlic Mashed Potatoes

Ingredients

• 0.5 cup balsamic vinegar 
• 0.3 lb plus 1 tablespoon butter 
• 2 cups wine dry red
• 3 cups fat-skimmed beef broth low-sodium
• 0.3 cup mint leaves fresh chopped
• 2 tablespoons thyme leaves dried fresh
• 30 cloves garlic peeled
• 0.5 cup olive oil extra-virgin
• 1 tablespoon parsley italian chopped
• 0.3 teaspoon pepper 
• 1.8 pounds russet potatoes peeled cut into 1 1/2-inch chunks
• 0.5 teaspoon salt 
• 4 oz shallots chopped
• 1  fat-trimmed lamb loin 
• 0.5 cup whipping cream 

Equipment

• frying pan
• oven
• whisk
• blender
• baking pan
• potato masher
• grill
• kitchen thermometer
• aluminum foil
• microwave

Directions

1. Rinse lamb and pat dry. Chop 10 cloves of garlic. In an 8- by 10-inch baking dish, mix half the chopped garlic, 1/2 cup olive oil, vinegar, shallots, thyme, parsley, 1/2 teaspoon salt, and 1/4 teaspoon pepper.
2. Add lamb and turn to coat. Cover and chill at least 4 hours or up to 1 day, turning occasionally.
3. On a 12- by 12-inch sheet of foil, mix remaining 20 cloves garlic with 1/2 tablespoon olive oil to coat; seal foil around garlic.
4. Bake in a 350 regular or convection oven until cloves are soft when pressed, about 45 minutes, turning packet over halfway through baking.
5. While garlic is baking, in a 10- to 12-inch frying pan over high heat, boil wine until reduced to 1 cup, about 10 minutes.
6. Add broth and boil, stirring occasionally, until mixture is reduced to about 1 1/2 cups, about 20 minutes.
7. Whisk in 1 tablespoon butter, then stir in mint and the roasted garlic. Keep warm over low heat.
8. In a 5- to 6-quart pan, combine potatoes and remaining chopped garlic; add water to cover. Bring to a boil over high heat; cover, reduce heat, and simmer until potatoes mash easily when pressed, 20 to 25 minutes.
9. Meanwhile, heat cream with the remaining 1/2 cup butter in a microwave-safe container in a microwave oven at full power (100%), stirring at 20-second intervals, until butter is melted and mixture is steaming (do not boil), about 1 1/2 minutes total.
10. Drain potatoes and garlic. Mash with a potato masher or a mixer until almost smooth.
11. Add cream mixture and mash to desired consistency; if potatoes are thicker than desired, add a little milk.
12. Add salt and pepper to taste. Keep warm over low heat if necessary.
13. While potatoes cook, lift lamb from marinade and drain well (discard marinade).
14. Lay on a barbecue grill over a solid bed of medium-hot coals or medium-high heat on a gas grill (you can hold your hand at grill level only 3 to 4 seconds); close lid on gas grill. Turn occasionally until lamb is browned on all sides and a thermometer inserted in center of thickest part reaches 135 for medium-rare (pink in the center), 20 to 25 minutes, or until done to your liking.
15. Transfer lamb to a board and let rest in a warm place at least 5 minutes.
16. Mound mashed potatoes equally on plates.
17. Cut and remove string from lamb; slice loin crosswise and fan slices over potatoes. Spoon sauce with garlic around meat and mashed potatoes.
18. Notes: Have the butcher bone a lamb loin (1 3/4 to 2 lb.; make sure you don't get a tenderloin or the sirloin) and roll and tie it into a roast about 8 inches long and 2 1/2 inches wide. You can marinate the lamb and prepare the sauce through step 3 up to 1 day ahead; bring sauce to a simmer over low heat before serving.
19. Pour Buttonwood Farm Winery's "Trevin" Bordeaux blend to match the Cabernet sauce here.