Can you make Tarte Tatin with frozen apples?

It's possible, but you're gonna get worse results than with fresh apples. The thing is, frozen apples lose a ton of water during freezing, so they're gonna release less juice while cooking. So you risk ending up with a thinner, less shiny caramel layer in the end, and the apples themselves might be a bit softer and less structured.

If you really wanna use them, you gotta thaw them completely before cooking and drain them well to get rid of as much water as possible. After that, use them like fresh apples: melt the butter with the sugar in the pan, arrange your apples nice and tight (and you can add a bit more since they'll have released water), then pour your puff pastry on top and bake like usual. The cooking might take a few extra minutes.

Honestly, if you have the choice, go with fresh apples. But if you're in a pinch or that's all you've got on hand, it still works. Just be aware that the final result won't be as "restaurant quality" as the classic tart, with less spectacular caramel. It's still good to eat, but yeah.