Bring a large pot of salted water to a boil. Add the lobster tails and simmer until cooked through, about 8 minutes. Remove the tails from the water and let cool. Remove the meat from the shell, discard the shell and chop the meat into bite-size pieces.
Bring the water back up to a boil and add the potatoes. Boil the potatoes until very tender, about 30 minutes. Drain the potatoes and put them back into the pot.
Add the milk, butter, clam juice, soy sauce and wasabi paste. Mash the potatoes and blend in all the ingredients. Stir in more milk if the potatoes are too dry. Gently stir in the tarragon and lobster meat. Season with salt and pepper. Serve warm.
This recipe was created by a contestant during a cooking competition. The Food Network Kitchens have not tested it for home use, therefore, we cannot make any representation as to the results.