This New England classic sticks to tradition, but with a few easy enhancements. Michael Ruhlman dresses succulent chunks of freshly steamed lobster with homemade tarragon mayonnaise and adds crunchy celery, lemon, and cayenne for brightness. Pile it high in a butter-toasted split-top roll: it’s heaven.
Part 1: Add 1–2 inches of water to a large pot and cover with lid; bring to a boil over high heat. Place the lobsters into the pot, replace cover, and steam for 10 minutes.In a small bowl, combine minced shallots and lemon juice. Let macerate for 10 minutes.
Place 1 cup homemade mayonnaise into a bowl. Add 2 tablespoons of the macerated shallots, along with 1 teaspoon of juices, to the mayonnaise. Add minced tarragon, and stir to combine. (Note: This makes enough tarragon mayonnaise for 4 lobster rolls). Slice celery stalks into thin strips lengthwise, then cut into ¼-inch dice. Set aside.
Part 2: Prepare an ice bath by placing ice cubes in a large bowl of water. After 10 minutes of steaming, remove lobsters from the pot and immediately place in the ice bath to stop the cooking. Let chill, 5–10 minutes. Meanwhile, in a large bowl, combine the sliced celery and tarragon mayonnaise.
Toast buns: Heat a skillet over medium heat. Spread softened butter over the inside and outside of the buns. Working in batches, open up the buns to place them flat on the skillet to toast, about 1 minute. Flip and toast the other side, 1 more minute. Repeat until all of the buns are toasted.
Part 3: When cool enough to handle, break down the lobster. Use paper towels to absorb any liquid that drains out. First, twist off the tail from the body and set aside. Repeat with the legs (which you can save for stock or discard), claws, and knuckles. Remove the tail meat from its shell by splitting the underside of the tail in half lengthwise. Remove the meat from both halves and set aside (clean out the green tomalley or roe and discard).Use a knife or a lobster cracker to split the claw shells; remove the meat and set aside with tail meat. Crack the knuckle shells, remove the meat, and set aside with remaining lobster meat. Repeat with remaining lobster.
Place a large mixing bowl on top of a kitchen towel. (This will keep the bowl stationary during whisking.) Into the bowl, add the egg yolk, a pinch of salt, 1 teaspoon lemon juice, water, and a pinch of cayenne pepper; whisk to combine. Begin emulsifying: whisk in a drop of olive oil, then whisk in a tablespoon in a thin steady stream. Switch to vegetable oil (since the strong flavors of olive oil can over power the may): add about 1/3 of it in a thin, steady stream while whisking continuously. Alternate whisking in olive oil and vegetable oil until all of the oil has been added. As the oil is whisked in, the emulsion will thicken, eventually holding a peak off the tip of the whisk. Taste the mayo; then whisk in remaining 2 teaspoons lemon juice, a few pinches of salt, and a pinch of cayenne to taste. Set aside. makes 1 1/2 cups. (Mayonnaise can be stored up to a week in the fridge.)
Assembly: Roughly chop lobster meat into big chunks. Add a few tablespoons of the tarragon mayonnaise, just enough to coat the meat. Taste and adjust seasoning with salt, pepper, or more mayonnaise as needed. Place lobster salad into toasted buns. Garnish with lemon wedges and watercress, and serve.