Preheat oven to 325°.
To prepare crust, combine cracker crumbs and butter in a bowl; toss with a fork until moist. Press into bottom of a 9-inch springform pan coated with cooking spray.
To prepare the filling, beat cheeses at high speed of a mixer until smooth. Add sugar, milk, and vanilla, beating well. Add eggs and egg whites, 1 at a time, beating well after each addition. Pour half of the cheese mixture into another bowl. Add chocolate to remaining batter. Pour one-third of white batter into prepared pan. Pour one-half of chocolate batter in center of white batter in pan; spread to within 1 inch of edge of white batter. Pour one-third of white batter in center of chocolate batter; spread to within 1 inch of edge of chocolate batter. Pour remaining chocolate batter in center of white batter; spread to within 1 inch of edge of white batter. Pour remaining white batter in center of chocolate batter; spread to within 1 inch of chocolate batter. (Design on top should look like a target.)
Bake at 325° for 1 hour and 10 minutes or until almost set. Cheesecake is done when center barely moves when pan is touched. Remove cheesecake from oven; run a knife around outside edge. Cool to room temperature. Cover and chill at least 8 hours.