Heat the olive oil or butter in a frying pan over a medium heat, then cook the leeks with a pinch of sea salt for 10 mins, stirring frequently until softened. Transfer to a plate and leave to cool for 3-4 mins.

Meanwhile, whisk the crème fraîche, eggs, a good grinding of black pepper, lemon zest and a pinch of sea salt with half of the dill.

Heat the oven to 200C/180C fan/gas 6. Leaving the puff pastry on its baking parchment, unroll it into a small rectangular roasting tin (we used a 24 x 20cm tin), so that the pastry comes up the sides. Trim the shorter overhanging ends of the pastry, if you like – they’re great for making cheese straws.

Spread the cooled leeks all over the pastry base. Arrange the smoked salmon on top, then pour over the egg and crème fraîche mixture. Season with black pepper and bake for 25-30 mins until there’s no wobble and the pastry is golden.

Leave to cool for 10 mins before serving with the remaining dill scattered over. Will keep chilled for up to two days. Reheat until piping hot or serve cold.