The day before, wash the potatoes and cook them in their skins. Let them rest briefly in the cooking water, then peel while hot. Cool completely.
Bone the guinea fowl, reserving the breasts. Gently crush the carcasses and trimmings. Wash and slice the carrots, celeriac, and leeks.
Place the carcasses in a large pot with the sliced vegetables, bay leaf, juniper berries, and cloves. Add 2 liters of water and simmer for 1 1/2 to 2 hours. Strain and reduce the stock by half.
Pass the cooked potatoes through a ricer or food mill. Mix in the flour and egg to form a smooth dough. Season with salt, pepper, and a pinch of nutmeg. Roll into finger-sized lengths and poach in salted boiling water for 2 to 3 minutes.
Season the guinea fowl breasts with salt and pepper. Sear on both sides in hot clarified butter, then finish in a 120°C oven for 8 to 10 minutes.
Meanwhile, wash and slice the leeks. Sauté in butter, deglaze with 100 ml of the guinea fowl stock, and mount with 2 tablespoons cold butter.
Wash the spring onions, trim the stems to length, and quarter the bulbs. Sauté in hot butter, add a splash of stock, and cook until tender but firm.
Sauté the disguised potatoes in hot butter until golden. Slice the breasts and plate with leeks, potatoes, and spring onions. Drizzle with reduced poultry jus.
Source: La Nouvelle Cuisine for all seasons
