Put the lobsters in a large pot of cold salted water. As soon as the water is boiling, cook for 8 minutes.Remove the lobsters from the pot. Let cool.Meanwhile, mix all the other ingredients for the tartare sauce. Set aside.Shell the lobsters. Remove the meat and reserve the coral.Cut the meat into small pieces.Add a bit of coral to the tartare sauce to flavor and color it, and mix.Place the lobster meat in a large bowl, add the tartare sauce to taste.Mix gently. Season to taste.Serve the tartare in individual plates using a pastry ring.Serve with a rocket salad and croutons.