Line a 23cm square baking tin with parchment. Preheat oven to 170C.
Peel, core and dice the cooking apples into half inch cubes. Add to a pan on low heat, and stew until almost collapsed – a few chunks is nice. Let cool.
Put butter and syrup in a largish saucepan and melt gently together. Stir in the sugar, oats and salt and mix well.
Press half the mix into the lined tin. Spread a 1cm layer of the cooled stewed apple, and then carefully top with the remainder of the oat mix, pressing down lightly. Bake for around 30mins until golden. Let cool in the pan until easy to handle, before turning out onto a board, and chopping carefully into squares. Can be served warm with cream or custard!