Ellen DeGeneres -- I Just Made a FORTUNE ... Flipping My New Mansion

Ellen DeGeneres just flipped the amazing house she bought around New Year's -- after only living there a few months -- and the buyer was Napster co-founder Sean Parker ... who opened his wallet wide.

The Brody House -- yes, the place is so baller it has a name -- was sold to Parker for $55 million ... which means Ellen made a tidy $15 mil profit. She bought it for around $40 million. We're good at math.

We're told Parker approached Ellen and Portia late last month with the offer ... he went nuts over the famous house and Ellen's interior design. We're told even though she never intended to flip the house, she couldn't refuse a good deal. The escrow was all of 8 days. It closed last Thursday.

Ellen and Portia quickly snatched up the entire floor of a condo in Beverly West (fancy schmancy condo near Bev Hills) for $16 mil ... combining two units for new digs. But when they want real space, they'll go to their mega-estate is Santa Barbara.

We called their broker -- uber-real estate agent Kurt Rappaport -- but our calls weren't returned.

The rich get richer.