For Mint Glaze: Place jelly, wine, mustard and pepper in a blender; cover and mix until smooth.
For Lamb: Preheat oven to 425 degrees.
Cut slits all over lamb with tip of sharp knife; insert garlic slivers; season with salt and pepper.
Place lamb in shallow roasting pan.
Bake uncovered, on center rack for 1 hour.
Remove from oven; reduce temperature to 375 degrees.
Brush about 1/2 cup Mint Glaze over lamb; return to oven and bake an additional 40 to 45 minutes.
Remove from oven; insert instant-read meat thermometer into the thickest part of meat - temperature should read 155 degrees for medium.
Brush remaining glaze over lamb; loosely cover.
Let stand for 15 minutes before carving.
Place lamb on serving platter; garnish with fresh mint.
Ready in 2 hours.