Sprinkle the washed and cleaned turkey inside and out with salt and black pepper.
To prepare the stuffing, grate several slices of old bread into a separate container or blend them in a blender. Mix the crumbs with the finely chopped onion and braise the mixture in 2 tbsp butter.
Add the washed and finely chopped mushrooms, season with a little salt and black pepper and fill the turkey with this stuffing. If necessary, sew the opening of the turkey closed.
Place it in a buttered tray, smear the entire turkey with butter generously and pour in some water to the tray. Put it to bake in a moderate oven, basting it with the sauce from the tray the entire time.