Cook the pasta in a large pot of boiling salted water until al dente.
Using a mortar and pestle, mash the salt and garlic cloves together into a paste. Warm the yoghurt slightly in a saucepan. Remove a small amount of warmed yoghurt from the pan and stir together with the garlic paste. Stir this mixture into the remaining yoghurt.
Drain the pasta and rinse in cold water. Place in a casserole dish, toss with 1 tablespoon butter or margarine. Toss with half of the garlic-yoghurt sauce. Spread the remaining sauce over the pasta. Garnish with the parsley.
For a very special dish, brown the pine nuts in 2 tablespoons butter or margarine. Pour over the parsley. Serve immediately.