gistfile1.rb

class User < ActiveRecord::Base

  has_one :candidate_profile

  alias_method :candidate_profile_without_initialization :candidate_profile
  def candidate_profile
    candidate_profile_withough_intitialization || build_candidate_profile
  end

end

user = User.last
user.candidate_profile # => super: no superclass method `candidate_profile' for #<User:0x10c639a90>

Just tried this in a simple rails app. This approach seems to work.