How to remove nested keys from a hash list in Rails

I am now trying for some hours to remove a nested hash key of a hash list. I saw many solution non-nested hashs wich looks like this:

   sample_hash = {"key1" => "value1", "key2" => "value2"}
   sample_hash.except("key1") 

This results in:

  {"key2"=>"value2"}

But if I try to use the except method on a hash with nested key then it doesn't work. Here my code:

  nested_hash = {"key1"=>"value1", "key2"=>{
                                           "nested_key1"=>"nestedvalue1",
                                           "nested_key2"=>"nestedvalue2"
                                           }
                }

  nested_hash.except("nested_key2")

The except() method returns the nested_hash without any changes. I have looked for a solution how I can pass nested hash-keys to the except method, but couldn't find anything. Is it even possible to pass nested keys to this method or should I use some other method which deletes a nested hash key from my hash list?

what about

Hash[nested_hash.map {|k,v| [k,(v.respond_to?(:except)?v.except("nested_key2"):v)] }]

=> {"key1"=>"value1", "key2"=>{"nested_key1"=>"nestedvalue1"}}

ugh.