2 tblspns butter
2 shallots, finely chopped
freshly ground pepper
2 tblspns cognac
2 cups dry white wine
1 bay leaf, 1 sprig thyme, 3 sprigs parsley
6 tblspns doublecream
2 egg yolks
2 pinches cayenne pepper
2 tblspns chopped fresh tarragon
Melt the butter in a non-stick pan. Add the prawns, cover and cook for 5 minutes. Add the shallots, season with pepper and cook, stirring over low heat for 2 minutes.. Pour in the cognac and ignite, shaking the pan gently until flames subside. Add the wine and bouquet garni and cook over high heat, stirring, for 2 minutes. Remove prawns with a slotted spoon and keep warm.
Boil the cooking liquid until syrupy, about 5 minutes. Add half the cream and cook for 2 more minutes. Remove the bouquet garni.
Beat the egg yolks with a fork; beat in the remaining cream. Pour into the saute pan and remove from heat; stir with a wooden spoon until the sauce is smooth and thickened. Add the prawns and cayenne and reheat, stirring, for 30 seconds.
Turn the prawns and sauce onto a large platter, sprinkle with chopped tarragon and serve immediately.