Chicken Casserole with breasts

olive oil 5 whole skinless chicken breasts (approx 150g-175g a breast) 2 leeks , sliced 4 garlic cloves , crushed 200 g button mushrooms , some halved and[...]

2 tablespoons light margarine 1 garlic clove , minced 6 tablespoons flour 1 1/4 cups chicken stock, defatted 1 cup skim milk 1/2 teaspoon salt 1/8 teaspoon[...]