Using a vegetable peeler, slice the courgettes into pappardelle-style strips. Peel and cut the apple into equally thin pieces.
In a large serving bowl, whisk together the lemon juice and oil, and toss the courgette and apple in it.
Toast the hazelnuts in a dry frying pan for 2 to 3 minutes, until fragrant. Transfer them to a board, roughly chop them and sprinkle lightly with sal