Change the baking time and/or temp if using apples instead?

I haven’t made it with apples, but I have with Bosc pears. I agree with AJ about cutting the fruit very thinly. I otherwise made it as written. AJ's other suggestions sound amazing. That said, the advantage of not adding anything else such as apple butter or melted butter is that with such a relatively dry fruit, the topping caramelizes beautifully and shatters a little when you cut into it. I love that little crunch.

I would make several adjustments:

I'd cut the apples very thinly.

I'd put a layer of apple butter or thick apple sauce down before arranging the apple slices.

I'd bake at 400 degrees for 40 minutes, tenting if necessary to keep the crust from burning.

At about 30 minutes, I'd take the tart out and quickly brush melted butter all over it, then return it to the oven.

I'm tempted now to try this! If you try it, do let us know, please, how it turns out. ;o)