Preheat the oven to 200°C.
Cut through both sides of the chicken backbone with kitchen scissors and remove it.
Press the chicken flat onto a roasting tray and turn it breast side up.
Mix maple syrup, lemon juice, mustard, and thyme in a bowl.
Season the chicken and coat the skin with the maple syrup mixture.
Roast the chicken and the foil-wrapped garlic for 20 minutes.
Remove the soft garlic and continue roasting the chicken for another 25 minutes.
Rest the cooked chicken for 5 to 10 minutes before carving.
Squeeze the roasted garlic into a food processor.
Add wine, vinegar, mustard, egg yolks, Worcestershire sauce, and parmesan and blend.
Stream in the rapeseed oil while blending until the dressing emulsifies.
Coat bread cubes in olive oil and rosemary, then fry until golden.
Toss lettuce with hot croutons and dressing and serve with the chicken.