2) Add the clam juice, bring to a boil and simmer, uncovered, until the vegetables are tender, about 20 minutes.
3) In a small pot, melt the remaining butter and whisk in the flour. Cook over very low heat for 3 minutes, stirring constantly. Whisk in a cup of the hot stock and then pour this mixture back into the cooked vegetables. Simmer for a few minutes until the stock is thickened.
4) Add the milk and clams and heat gently for a few minutes to cook the clams. Taste for salt and pepper. Serve hot.