Kill the lobster, preferably with a butcher knife through the head (this has been proven to be the most humane way of killing crustaceans): Holding the lobster on a cutting board, plunge the knife into the head. Then pull the knife down and forward, splitting the front of the head in two; this kills the lobster instantly
Or plunge the lobster into a large pot of boiling water for 1 minute. Cut the lobster lengthwise in half; make sure to save all the juices released from the lobster. Crack the claw shells.
Heat 2 tablespoons of the butter in a large skillet over medium heat. Sauté the garlic and shallots for 3 to 4 minutes, until soft. Add the lobster to the pan and sauté for 4 to 5 minutes. Pour over the white wine and the reserved lobster juices, sprinkle with most of the tarragon, cover, and simmer for 15 minutes.
Transfer the lobster to a warm serving platter. Continue cooking the juices until reduced to half. Season with curry powder, salt, and the rest of the tarragon. Stir in the remaining 6 tablespoons butter and let it melt, then pour the sauce over the lobster and serve with lots of good bread to sop up the cooking juices.