-
1
Whisk wine, shallots, mustard, 1/3 cup chopped sage, oil, and garlic in medium glass bowl.
-
2
Transfer 1/2 cup marinade to small bowl; reserve for sauce.
-
3
Cover and chill.
-
4
Place leg of lamb in 2-gallon resealable plastic bag.
-
5
Pour remaining marinade into bag; seal.
-
6
Turn bag to coat, arranging lamb in 1 flat piece.
-
7
Place lamb in marinade on rimmed baking sheet. Chill overnight, turning occasionally.
-
8
Combine reserved 1/2 cup marinade and beef broth in small saucepan.
-
9
Boil until reduced to 3/4 cup, about 12 minutes.
-
10
Cool, cover, and chill.
-
11
Prepare barbecue (medium heat).
-
12
Remove lamb from plastic bag and transfer to large rimmed baking sheet with some marinade still clinging.
-
13
Open lamb like book and sprinkle on both sides with salt and pepper.
-
14
Transfer lamb to grill.
-
15
Cover and grill until charred and instant-read thermometer inserted into meat registers 135u00b0F for medium-rare, about 10 minutes per side (some thicker pieces can be cut away from leg and grilled longer if desired).
-
16
Transfer to work surface; let rest 10 minutes.
-
17
Rewarm sauce.
-
18
Whisk in butter and remaining 1 tablespoon chopped sage.
-
19
Season to taste with salt and pepper.
-
20
Thinly slice lamb against grain. Transfer to platter.
-
21
Spoon some of sauce over. Garnish with fresh sage sprigs, if desired.
