McDonald's Commands a Real Estate Empire in Russia By ERIN E. ARVEDLUND MOSCOW, March 16 - The busiest McDonald's restaurant in the world is not in America but thousands of miles away in Pushkin Square. The store serves 30,000 customers a day, as busy as on opening day, Jan. 31, 1990. The menu is essentially the same as in the United States, with the addition of cabbage pie among other traditional Russian food items. The Pushkin Square restaurant is important as well because it is the jewel in a growing real estate empire that ranks McDonald's among the largest corporate...