Preparation

1. Preheat oven to 210°C (gas mark 7). Chop the tarragon. Prepare vinaigrette: mix olive oil, balsamic vinegar, chopped tarragon and orange zest, then add fleur de sel and ground pepper. Set aside.

2. Wash the beets. Remove the stems and tops without cutting the bulb, and set aside. Mix the coarse salt with a few spoonfuls of water. Set aside a cup of salt in case you need to cook them longer. In a cast-iron casserole dish, spread half the salt (3 cm thick). Press each beet into it. Cover completely with the remaining salt, wrapping each beet separately. Bake for 1h30.

3. Separate the leaves from the stems and steam them separately, 3 min for the leaves and 5 min for the stems. Rinse under cold water. Squeeze dry, dip in vinaigrette and set aside.

4. Test beet cooking in the oven: plunge a knife into the heart of a beet, and the blade should sink in without resistance. If necessary, cover again with a little wet salt and cook for a maximum of 15 min. Remove from the oven and leave to cool for 15 min. Break the salt crust and remove as much as possible with a pastry brush. Peel the beets, slice if necessary and drizzle with the orange zest vinaigrette. Serve at room temperature, or chill overnight to enhance the flavor of the orange zest and tarragon.