Justin Bieber and Selena Gomez Grab Breakfast Together One-on-One

Justin Bieber and Selena Gomez had quite a weekend away from The Weeknd ... they grabbed breakfast together Sunday morning -- just the 2 of 'em.

JB and Selena were chatting it up at a cafe in Westlake Village ... with Bieber rockin' a hoodie, and Selena not wearing much to cover up.

This is the 3rd sighting recently where the 2 exes have hung out ... again, with Abel nowhere in sight. Justin was just at Selena's house last Sunday ... and stayed 'til midnight.

Like we told you ... Selena's BF was fully aware of them hanging out, and we're told he's totally cool.