In an oven-proof casserole dish approximately 12" x 8," cut the clove of garlic and rub the dish thoroughly with the clove of garlic and lightly butter. Take the leeks that has been washed, trimmed and cut into 1-inch pieces. Gently soften the leeks in a non-stick frying pan with half a teaspoon of butter until soft and tender. Remove from pan and place in bottom of casserole dish. Take the potatoes and slice them approximately 2/8-inch thick and do the same with the parsnip. Start to place the potatoes in the casserole dish on top of the leeks, adding a piece of parsnip at regular intervals. When the dish is packed full of potatoes and parsnips, season it well with salt and pepper. Add the cream, goat cheese and grated parmesan cheese and bake in a preheated oven at 300 degrees Fahrenheit for 1 hour to 1 hour and 15 minutes or until the potatoes are fork tender and have turned a light golden brown. Sprinkle with chopped parsley and serve.