Saute leeks in butter for 5 minutes. Add meat and brown, add onions nad saute until golden, add tomato sauce, salt, coriander, cumin, pepper and cayenne, simmer 30 minutes. cook noodles as directed. combine yogut and garlic, stir well. Butter a 13x9 inch baking pan, put half yogurt on the bottom, layer with 1/2 noodles, 1/2 meat sauce, repeat ending in meat sauce. sprinkle mint over top and bake for 35 minutes at 350 degrees