The gentleman whose yard this plant is growing in doesn't eat the fruit and has no idea what it is. It was in the yard when he bought the house. It's a cool looking cactus from above!
From my quick bit of research, I believe it's a Peruvian Apple Cactus. The images match the plant and the fruits:
The fruit is smaller and smoother (no wings) than the Dragon fruit. The edible innards are similar in appearance to the dragon fruit, but the seeds are larger and the flesh isn't quite as sweet - it's got a different texture as well. It's perfectly edible, nonetheless.
Here's a quick video:
I'm not keen on prickly plants in my yard, so I'll have to figure out where I could grow this "out of the way". What I like about the Dragon fruit is that it's a climber.
Here's a picture of my neighbor's Dragon fruit. Talk about magnificent!!!
It was out of sight, out of mind. Just growing happily away in my neighbor's back yard for years and years. Just look at all those droopy flowers! I just took these pictures a little while ago. This is growing up a giant Royal Poinciana tree, probably planted when the house was built in the 60's.
The Dragon fruit was planted by our ex-door neighbors who were living in the house next door when we bought our house in 1992. We believe they bought theirs in the early 80's. They moved away (hence the "ex-door neighbors") in the late 90's. There have been two owners since then. We have no idea when the Dragon fruit was actually planted, or how long it has been bearing fruit.
All I know is I am secretly hoping our neighbor didn't care for the fruit we picked and left on her porch last night!