Soak top and bottom of clay cooker in water about 1 minutes; drain.
Place onion, garlic and bay leaf in cooker. Cover with chicken quarters, skin side up. Spread chicken evenly with mustard; sprinkle with nutmeg. pour in wine.
Place covered cooker in cold oven. Set oven at 475 F (250 C). Bake until chicken is almost tender, about 45 minutes. Remove chicken. Place cabbage wedges in cooker. sprinkle with salt and pepper. Place chicken quarters over cabbage wedges. Bake covered until cabbage is crisp-tender, 20 to25 minutes.
Remove cover; bake until chicken is crisp and brown, 5 to10 minutes. Remove chicken and cabbage to serving platter; spoon a little of the cooking liquid over chicken and cabbage.