The custardy interior tastes much like lemon meringue pie filling. I add it to smoothies in frozen form made with just this fruit and fresh squeezed orange juice to get a creamy, Orange Julius-type, super-yummy beverage. A few ice cubes keep it from being overly sweet.
They turn yellow when ripe. Don't eat the seeds, ever, but grow more trees with them if you have room in your yard (and freezer) for them.
Preparation goes like this: Halve ripe fruit, pull out the core.
Then scrape out the custard from the core area to just where you expose the tips of all the seeds embedded in the remaining flesh (see 3rd photo below). Dig each seed out (it's a little messy) and then scoop the custard into containers to freeze.
The skin has a habit of staining things, so don't wear your best clothes or put them cut side down on your cutting board.