Go to Settings and click on "Labs" and Enable the option "Undo Send".
After activating the feature, Go back to the "Settings" and scroll down to select the time period to recall a email. You can set from 5 sec to 30 sec.
Make sure the option "Enable Undo Send" is ticked under the "General" tab.
Send a test email to one of your other email and once the confirmation message "Your message has been sent. Undo View message" is shown, you can click on "Undo" to recall the email.
Note:- if you take longer then the 30 seconds then you will not be able to recall a email.
