Lay the puff pastry on a sheet of baking paper and score it with a knife about 2 cm in from the edge, all the way round.
Bake the pastry in a preheated oven for 10 min. at 200°C, – conventional oven (top and bottom heat).
Let the pastry cool slightly, then spread the base with the cream cheese or mascarpone. Spread with gentle strokes, and try not to lift the spoon too much, as that pulls the pastry up. You can dip the spoon in boiling water and spread the cheese with the back of it – it makes the job much easier.
Arrange the potato slices, basil leaves and goat's cheese over the base, and season with salt and pepper.
Return the tart to the oven for a further 12-14 minutes – still at 200°C.
Let the tart cool slightly, then top with the pesto, fresh rocket and roughly chopped hazelnuts.Drizzle with a little olive oil if you like - and add extra freshly ground pepper.