Clean the beet and cook unpeeled in salted water for 40 minutes. Meanwhile, clean the chard, remove the stems. Blanch leaves in plenty of salted water for one minute.
Drain, spread out on kitchen paper and pepper.
Cut the feta into four equal pieces and sprinkle with paprika powder. Then wrap tightly with 2-3 chard leaves. Steam the packets in a strainer or steamer, over boiling water in a closed pot, for 15 minutes. Peel the cooked beet and cut into sticks. Dice the onion and sauté in hot butter until translucent. Pour in wine and season well. Stir in crème fraiche.
Add the beet sticks and bring to the boil briefly. Serve sauce and chard parcels. Garnish with tarragon if desired. Serve with crispy rosemary potatoes.
