diff --git a/actionpack/lib/action_controller/routing/recognition_optimisation.rb b/actionpack/lib/action_controller/routing/recognition_optimisation.rb
index 306219a431d24aa11cd23e167a6d85684dd656f6..4935432d876df49a85826ebd453ef90435d8c648 100644
--- a/actionpack/lib/action_controller/routing/recognition_optimisation.rb
+++ b/actionpack/lib/action_controller/routing/recognition_optimisation.rb
@@ -134,6 +134,9 @@ def to_plain_segments(str)
         def write_recognize_optimized!
           tree = segment_tree(routes)
           body = generate_code(tree)
+
+          remove_recognize_optimized!
+
           instance_eval %{
             def recognize_optimized(path, env)
               segments = to_plain_segments(path)
@@ -149,12 +152,22 @@ def recognize_optimized(path, env)
         end
 
         def clear_recognize_optimized!
-          instance_eval %{
+          remove_recognize_optimized!
+
+          class << self
             def recognize_optimized(path, environment)
               write_recognize_optimized!
               recognize_optimized(path, environment)
             end
-          }, __FILE__, __LINE__
+          end
+        end
+
+        def remove_recognize_optimized!
+          if respond_to?(:recognize_optimized)
+            class << self
+              remove_method :recognize_optimized
+            end
+          end
         end
     end
   end