Combine cookies, sugar and butter. Press onto the bottom and 1-1/2 inches up the sides of a greased 10-inch spring form pan. Bake at 350 degrees for 10 minutes; cool completely.

In a mixing bowl, beat cream cheese, sugar, eggs and sour cream just until blended. Add chocolate. Pour into crust. Bake at 350 degrees for 1 to 1-1/4 hours or until center is nearly set. Cool to room temperature, about 2 hours.

Combine sour cream, sugar and extract; spread over filling.

Bake at 450 degrees for 5-7 minutes or until set. Chill, uncovered, 1 hour.

Arrange oranges on cheesecake. Cover and chill at least 4 hours.