Chop vegetables roughly and place them in an ovenproof dish along with white wine and potatoes, with a rack on top.
Remove the backbone from the chicken by cutting down each side. Use the backbone to add flavor to the stock, so it should be placed together with the vegetables.
Spread the chicken out with the breast side up.
Cut the butter into smaller pieces and distribute the butter under the skin.
Season the chicken with salt and pepper and place it on the rack over the vegetables. Roast it for 45 minutes at 200 degrees Celsius (392 degrees Fahrenheit) with a convection oven (if the chicken has not been flattened and had the backbone removed, add 15 more minutes of cooking time).
Take the chicken out and let it rest.
Remove the backbone and discard it.
Blend the vegetables together with the stock to make the sauce and place the potatoes in the oven, turning it up to 225 degrees Celsius (437 degrees Fahrenheit) on the grill setting.
The sauce should be enriched with 100 ml of cream and seasoned with salt, sugar, pepper, lemon juice, and vinegar.
When the sauce is ready, take the potatoes out and cut the chicken into suitable pieces - either 4 or 8 pieces.
