Michael Douglas -- B-Day Celebration at Outback Steakhouse

Michael Douglas took advantage of the senior discount at an Outback Steakhouse in New Mexico yesterday to celebrate his 69th birthday.

M.D. drudged along to his car with a friend after the meal ... no sign of ex Catherine Zeta Jones -- who he's reportedly trying to mend relations with.

We're not sure what he ordered ... but if it wasn't a bloomin' onion, then SHAME!!!