--extra-headers Not assigning Cookie Value

[Muhammad-F-a-h-a-d]

I am running this command in the CLI,
lighthouse http://localhost:3000 --extra-headers "{\"Cookie\":\"monster=blue\", \"x-men\":\"wolverine\"}"

I want to set the Cookie item value, after running this command, this is the result

In Cookie Tag there's no items monster showing. I want to add a monster items and its value in the cookie .