I'm currently in the UK for Christmas. Amongst other Christmasy activities I cooked an apple pie. This differed from an American apple pie in one essential way. I used bramley apples.
There can't be any debate. Bramleys make the best apple pies. The American family members with me, who helped eat the pie, agreed.
They are sour to eat and the sourness turns to yumminess when cooked, which is why they are called cooking apples in the UK. For cooking, Granny Smiths pale in comparison.
What I do not understand is how a country like the USA, that considers apple pies to be symbols of Amerincanness, doesn't grow apples that are any good for cooking apple pies.
Some American farmer would make a fortune if they got working on growing bramleys and so made American apple pies taste of something more than muted apple mush. I found a place near San Francisco that claims to do them, but I don't live in San Francisco and apparently they are available only at some market stand in SF at some unspecified time in September and only maybe. I had no problem buying Bramleys in December, in Tescos in the UK.