Peel and slice the carrots and bring them to the boil on the boiling plate, drain.
Add a sprig of tarragon and place inside the simmering oven until just cooked.
Place the butter, stock cube, flour and milk in a pan on the simmering plate and combine together using a whisk until a smooth sauce is formed, season.
Put the cooked carrots in a roasting dish, such as theBlue Italian Spode for AGA, and pour over the sauce, sprinkle with chopped tarragon and serve or chill to reheat later.