Pour the milk into a small nonstick pan. Add the onion, garlic, cloves and bay leaves and season well. Bring to the boil then add the bread and simmer, stirring occasionally, over a low heat for 5–10 minutes until the onion is cooked then carefully remove the cloves and bay leaves.
Carefully transfer the sauce to a blender and blitz till puréed. Return to the pan, adjust the seasoning, and continue to gently cook, stirring constantly, for a few minutes to thicken. Finish with butter and cream.