Heat oven to 400. Spray a lg skillet w/ cooking spray,, place over med-low heat. Add oil and leeks. Cook until tender. Remove from heat. In bowl, whisk 2 tbsp milk w/ flour. Whisk in remaining milk, salt, pepper, nutmeg and garlic.
Spray a 2-quart casserole dish w/ cooking spray. Arrange 1/2 the potatoes in dish in single layer. Sprinkle w/ leeks and goat cheese. Pour 1/2 of the milk mix over potatoes.
Layer remaining potatoes over mix, then pour remaining milk mix over potatoes. Cover. Bake 45 mins. Uncover and bake 25 mins, or until potatoes are tender. In bowl, stir together bread crumbs and parmesan cheese. Sprinkle over potatoes. Bake, uncovered about 10 mins, or until top is browned. Sprinkle top w/ parsley.