Wash the chicken, pat dry and tie the legs together with kitchen string. Season with salt and pepper. Place on a fat pan of the oven and drizzle with hot clarified butter. First roast in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 30 minutes.
In the meantime, wash the potatoes and boil them in water for 15-20 minutes. Afterwards drain cold, rinse and peel. Peel, wash and cut carrots into pieces. Clean and wash spring onions, also cut into pieces.
Spread the vegetables on the fat pan. Season with salt and pepper. Mix mustard and honey, pluck tarragon leaves. Spread the honey-mustard mixture on the chicken and sprinkle the leaves on top. Cook chicken and vegetables for another 30 minutes.
Deglaze with the stock. Arrange chicken and vegetables on a plate. Pour the sauce stock through a sieve. Bring to the boil briefly and stir in the sauce thickener. Season to taste with salt, pepper and lemon juice and serve.