Tarragon has long been one of my favourite herbs. It’s powerful aroma and taste can deceive cooks into over-doing it, using too much and overpowering a dish.
A casual conversation with a very knowledgeable groundsman in the walled garden of Hughenden Manor, provided me with an explanation about the two main different types of tarragon. I am often presented with herbs from friends’ gardens, along with other vegetables and the like. Russian tarragon, is what I’m often given, grows profusely in the early summer, but does not have the same intoxicating flavour of French tarragon. It’s leaves have a sweet flavour similar to anise or licorice, but it loses its potency if dried. However, it may be preserved in vinegar or olive oil to create an appetising condiment. Among herbs, tarragon is relatively recent, having been grown in cultivation only in the last five hundred years.
In France, tarragon is highly esteemed, and known as The King of Herbs. It provides the dominant flavour in béarnaise sauce. Tarragon also complements fish (especially shellfish), chicken, egg dishes, soup and grilled meats. I remember Prince Charles being very fond of Noisettes d’Agneau à l’Estragon, (sautéed lamb with a tarragon sauce), when I was Chef Saucier at The Savoy. Here is a simple version of that dish:- 
Noisettes d’Agneau à l’Estragon
Serves 4
600g of trimmed lamb fillet, cut into 8 even sized noisettes
25g unsalted butter
2 shallots, finely chopped
1 clove of garlic, crushed
100ml dry white wine
250ml stock, chicken or lamb
4 sprigs of tarragon
Teaspoon of arrowroot (optional)
Salt and milled pepper
Few drops of lemon juice
Heat the butter in a pan until it starts to foam. Add the noisettes, seasoning lightly on both sides. Brown them all over, for 3-4 minutes then keep warm in a serving dish. In the same pan, add the shallots and garlic, and stir until lightly browned over a gentle heat. Remove the tarragon leaves from the stalks, chop the leaves and put to one side, but chop the stalks and add to the pan. Add the wine and reduce by half, then add the stock, and reduce by half again, stirring to release any cooking sediments from the pan. Here you may thicken the sauce slightly, by the addition of the arrowroot diluted in a little water. Strain the sauce into a clean pan, pressing the shallots with the back of a spoon to extract as much flavour as possible. Add the tarragon to the sauce and season to taste, adding a little lemon juice. Add any juices released from the noisettes, then spoon the sauce over the meat, and serve with some sautéed spinach and Jersey Royals.