Combine 4 bone-in, skin-on chicken thighs, 4 chicken drumsticks, 16 peeled pearl onions, 1 bay leaf, 3 thyme sprigs, and 750ml of pinot noir. Cover and refrigerate for 12-24 hours.
Preheat the oven to 350°F / 180°C. Strain, reserving the wine, and separate the chicken, onions, and herbs. Simmer the wine vigorously, skimming, until reduced by half.
Pat the chicken dry and season with salt and pepper. Brown it in batches, skin side first, in 3 tablespoons of vegetable oil in a large ovenproof pot; remove.
Fry 150g of chopped bacon until golden; remove. Brown 400g of white mushrooms in the fat, then the onions, setting each aside.
Melt 60g of butter in the pot. Cook 3 minced garlic cloves, then 2 tablespoons of tomato paste. Stir in 7 tablespoons of all-purpose flour and cook briefly.
Gradually stir in 750ml of low-sodium beef stock, then the reduced wine. Return the chicken, bacon, mushrooms, onions, and herbs. Cover and bake for 45 minutes.
If the sauce is thin, simmer it uncovered on the stove until thickened. Season with salt to taste.
