The day before, wash chicken inside and out and pat dry. Mix beer, orange juice, 3-4 tablespoons sea salt and peppercorns. Put the chicken in the freezer bag, place it in a bowl and pour on the marinade.
Seal the bag. Leave in the refrigerator for about 12 hours, turning 1-2 times in between.
Preheat oven (electric cooker: 200°C/circulating air: 175°C/gas: level 3). Peel and slice the onion. Wash thyme, shake dry. Remove chicken and fill with onion and thyme.
Plug the opening with a skewer and tie up with kitchen string. Tie the legs together. Put them on a lightly oiled baking tray. Roast in a hot oven for about 1 1/4-1 1/2 hours until the meat on the legs comes off the bone.
Meanwhile, cook the egg for the salad for 1 minute. Dice baguette. Peel garlic and chop roughly. Heat 2-3 tablespoons of oil. Fry the bread until golden brown, add the garlic and fry briefly. Remove the bread.
Rinse anchovies, dab dry, dice 1 fillet very finely, cut the rest into pieces. Break egg, separate egg white and egg yolk. Mix egg yolk, mustard, crème fraîche, diced anchovies and lemon juice.
Season with mixed pepper, 1 pinch of sugar and salt if necessary.
Clean, wash, spin dry and chop the romaine lettuce. Chop the parmesan into shavings. Mix anchovies, bread cubes and dressing with the rest. Serve with chicken.