Preheat the oven to 180oC
Removing the flesh from the shell in one piece can be a bit tricky, but as taste rather than presentation is the most important factor, don't stress if bits of flesh break off. Crack the claws and again, carefully remove the flesh. Mix the lemon, tarragon and butter together and spread half of the paste into the base of the lobster shell.
Pile all the lobster meat back into the shells and dot flecks of butter over the top. Place in a heat proof serving dish, cover with foil and heat for fifteen minutes.