Preheat oven to 400 degrees F. In nonstick skillet cook leeks in 1 tablespoon olive oil over medium-low heat, 20 minutes, or until tender and beginning to brown, stirring occasionally. Remove from heat.
In bowl whisk 2 tablespoons of the milk into the flour. Whisk in remaining milk, salt, pepper, nutmeg, and garlic.
Coat 2-quart casserole or au gratin dish with nonstick cooking spray. Arrange half the potato slices in dish. Sprinkle with leeks and goat cheese. Pour half the milk mixture over potatoes, leeks, and cheese. Layer remaining potatoes; pour remaining milk mixture over all. Cover with foil.
Bake 45 minutes. Remove foil and bake 25 minutes more or until potatoes are tender. In small bowl stir together the bread crumbs and Parmesan cheese. Sprinkle on potatoes. Bake, uncovered, 15 minutes more or until topping is browned. Let stand 10 minutes before serving. Top with parsley. Serves 8.