"Que si" at the beginning of a question

[createdamadman]

So, I have the following:



¿Que si me gustan las manzanas? ¡Me encantan! De hecho, ahora estoy trayéndolas del supermercado.


I'm a bit unclear on the purpose of the "Que si" at the beginning. I get that she's basically just asking "Do I like apples?", but I know you could ask that by saying "A mí me gustan las manzanas?" or even just "Me gustan las manzanas?". So, I'm not sure what the "que si" adds. Mostly, I'm wondering if there are specific times when it makes more sense to use "que si" or it it's completely interchangeable (with not using it).

[Rusty]

Someone asked if she like apples, first.
She then verifies that that was the question asked.

Prefixing a question with que (a relative pronoun) and si (if) always refers back to a question just heard. The equivalent in English is "Are you asking/wondering if ...?"