Place spinach in colander in sink. Pour boiling water over spinach; cool.
Meanwhile, mix cream cheese and eggs in large bowl until blended. Gradually stir in milk. Stir in 1/2 cup feta.
Squeeze excess moisture from spinach. Add spinach to cream cheese mixture; mix well. Spoon onto 9-inch square baking dish; top with remaining feta. Cover.
Bake 50 min. or until center is set, uncovering after 30 min.