Jo this is my speciality. I have friends that travel from other planets to take part in the perfect tail which i have mastered over 30 years.
First the lobster must be COLD WATER.. Maine or Australlian is the best. I only cook tails, because I can't kill anything to eat it. So here's how to do it. You will most likely get it frozen,, Some people will stick it right into a pot of boiling water..... NO<NO<NO... you take the tails out of the freezer the day before and thaw them then run them under cold water about an hour before your ready to cook. Then you don't boil them you steam them, until white and fluffy. Then you remove from the steamer and let cool before cutting off the shell, ( I have some garden shears for this task, ask if you need details) Then arrange the tails back side up on a broiler pan and put them about an inch away from the heat source in a very hot broiler oven, check every minute or so, after about 3 minutes turn them on their backs and brush each tail with gobs of butter, then back in the broiler and watch as a touch of brown blisters the tips of the tail...REMOVE immediately. And go to heaven..... I LOVE LOBSTER......AAAAHHHHHH