Drop the lobster in boiling water for no more than 45 seconds. Separate the tail, body, and claws. Split the tail and remove the meat. Crack the claws and knuckles open and remove their meat. Save the body and shells, if desired, for other applications – otherwise discard. Cut the butter into small cubes. Place them in a small saucepan and add the water. Heat the 4 ounces of butter slowly – whisking it with the water until fully melted. Add the lobster meat. Cook the meat in the butter over low heat for a total of about 5 minutes. Check the claw and knuckle meat after about 3 minutes. When cooked, remove the meat from the butter and set aside to cool slightly. Cut the tail and knuckle meat in medium/large pieces. The claw meat will break up in your fingers. Set aside.

Before starting on the sauce, put a pot on the stove with heavily salted water for boiling the macaroni. Next, melt the remaining 1 tablespoon of butter in a medium saucepot over medium/high heat. Add the flour and cook for about 2 minutes, stirring often with a wooden spoon, until the mixture browns slightly and develops a nutty aroma. Stir in the cream and bring back up to a boil, stirring constantly. Add the milk and, again, bring to a boil. Reduce to a simmer and let cook for about 3 minutes. Add the cheeses, a handful at a time, and stir until fully incorporated. Add the morel powder.

When the water for the pasta has come to a rolling boil, add the pasta and cook al dente (see package for exact times). Dump the cooked pasta into a colander to drain off the water. Add the pasta to the sauce and stir together. Fold in the cooked lobster meat and serve right away.