Scott Disick -- Playing Catch-Up on Father-Son Time (PHOTO)

Scott Disick has begun the family healing process ... spending Wednesday with his son.

Disick took five-year-old Mason to Barnes & Noble in Calabasas, where the kid loaded up on toys.

Scott and Mason then went for an early dinner at Rosti Cafe.

Although he's been out of the picture for the past month following his split with Kourtney, Disick kept in touch from a far ... mostly thanks to FaceTime.