Minimum packages needed for simple MTA

I've used sendmail for years to send mail from a single computer to my 
ISP with mutt my mail client.  But it recently stopped working and I've 
given up trying to get my head around sendmail's obscure methods.

Mutt still works receiving mail with fetchmail and procmail, but I can't 
send mail, so I've had to use Thunderbird for this one.

What I'd like to know is whether there is a tutorial anywhere that would 
tell me which Linux Mint .debs I'd need to get mail from my computer to 
my ISP.

TIA

Frank