Crush the fennel seeds in a baggie.
In a small bowl combine fennel, butter, rosemary, garlic, salt and pepper.
Preheat oven to 450 with rack in the middle of the oven.
Pat lamb dry and place in roasting pan.
Sprinkle lamb generously with salt and pepper.
Rub half of butter mixture on and refrigerate the rest of the mix.
Roast the lamb till its golden brown on the outside about 30 minutes.
Decrease heat to 350 degrees and continue till internal temp of 135 is reached for about 45 minutes.
Transfer lamb to large platter keeping the juices and cover with tin foil to keep warm.
Skim fat from the juices and add broth and wine to the juices.
Place the roaster on medium high heat and stir to get scrapings circulating. Simmer till reduced by 1/2 or about 12 minutes.
Remove from pan and whisk in remaining butter mix.
Season to taste with salt and pepper.
Suggested serving cut lamb and platter with a spoon of sauce.