If your Pancake is giving you the option of using FTP for updates, but you don't want to use it, you need to give Pancake permission to write to its own files. To do so, you will need to change the owner of all of Pancake's files to be the same user that's running the web server.
Warning: You will need to use SSH for this. If you do not have SSH access to your Pancake, you will have to use FTP, or contact your web host for help.
If you already know which user the web server is running under, skip to the next command. Otherwise, to find out the user that's running the web server, the following command MAY help:
ps -ef | egrep '(apache|httpd|php-fpm)' | grep -v root | grep -v egrep | tail -n 1 | awk '{print $1}'
To change the owner of the Pancake directory, use the following command (replace "/path/to/pancake" with the right path to your Pancake's directory, and replace "owner" with the name of the web server user):
chown -R owner:owner /path/to/pancake
That's it! Your Pancake should no longer ask you to enter FTP details, and should let you always update without any problems.