If you don't have a heavy roasting pan, you can brown and roast
the lamb in a large ovenproof skillet with two-inch-high sides.
The seasoned butter can be prepared one day before using.

What to drink: Penmara Shiraz or Cabernet Sauvignon

Seasoned butter
6 tablespoons (3/4 stick) butter, room temperature
3 tablespoons fennel seeds, crushed in plastic bag with mallet
3 large garlic cloves, minced
2 tablespoons Dijon mustard
1 1/2 tablespoons soy sauce
1 tablespoon coarsely ground black pepper
1 1/2 teaspoons dried crushed rosemary