Peel and grate potatoes into a large bowl using the biggest holes of a box grater. After grating, rinse the potatoes with cold water to remove excess starch. Squeeze with a towel to remove extra moisture. (You're about to add a ton of moisture with the persimmons.)
Grate (but don't peel) the persimmons into the bowl with the potatoes.
Peel the onion, and grate into the bowl using the finest setting on the box grater. You're basically adding onion paste.
Add the eggs, cinnamon, cumin, salt, pepper, corn starch, flour, and nutmeg to the bowl. Stir together until well combined. You want a wet mix, but if it looks like soup, add a bit more flour (one tablespoon at a time). You need the latkes to hold together in the hot oil.
Heat 1/2 cup of oil in a large pan over medium-high heat. Add a quarter cup of latke mix at a time and let each latke fry for about four minutes on each side. You want a nice, light brown color. Be sure not to crowd the pan – you should be able to fit two or three at once, but will need to do many batches. If your first couple of latkes have trouble sticking together, you can add more flour or another egg to the mix. You'll almost definitely need to keep adding oil to the pan to get through all your latkes.
Once fried, transfer each latke to a paper towel-lined plate to sop up the excess oil. (Careful not to stack too many latkes atop each other or else they'll get soggy again.)
For the black pepper sour cream: whisk the salt and pepper into the sour cream. Pretty easy! Adjust to taste. You want a strong black pepper vibe, but you also want to enjoy eating it.
Once everything's put together, place a couple of latkes on a plate and smear with sour cream. Delicately rain pomegranate seeds over the pile. Dig in and enjoy.