Cod with mussels and roasted cauliflower

Ingredients

• 1 kg mussels
• 1 clove garlic, finally chopped
• 2 onions, sliced
• 2 stalks celery, finally chopped
• 250 ml white wine
• 1 tablespoon butter
• pepper and salt
• 1 bay leaf
• thyme
• 4 cod fillets
• 500 g baby potatoes
• 1 cauliflower
• 2 tablespoons olive oil
• butter
• salt and freshly ground pepper