Place onion, cloves, bay leaf and milk in a saucepan over medium heat. Bring to the boil. Reduce heat to low. Simmer for 5 minutes. Remove from heat. Stand for 5 minutes.
Meanwhile, place bread in a food processor. Process until breadcrumbs form.
Strain milk mixture into a heatproof jug. Stir in breadcrumbs. Season with salt and pepper.