We spell it differently - pastie - and say it a bit differently too (I know you are all going to say we say EVERYTHING differently) The a is said to rhyme with car. But the actual food item looks the same.
Actually, here in the UK, the pronounciations are exactly the same. I'd say the spellings are too, but not sure if that's just that I'd spell them that way, or if it's universal.
LabRat