To prepare the dough, cream the butter and sugar (sachet 1) until pale and creamy, then mix in the egg yolk until combined. Add the dry mix (sachet 2) and mix to form a smooth dough – you will need to use your hands to bring the dough together. Press the dough into a thick disc, wrap in plastic wrap and chill in the fridge for 1 hour.

Preheat the oven to 160°C fan-assisted convection.

To prepare the blueberry filling, toss the blueberries in the lemon zest and juice. Mix the cornflour and sugar together and stir through the blueberries. Set aside until needed.

To assemble the galette, remove the chilled dough from the fridge and gently knead it until evenly pliable. Place between two sheets of baking paper and roll into a large rough circle, no thinner than 3mm. Don’t worry if the edges become a bit cracked and rugged. Remove the top piece of baking paper, and transfer the dough to a large baking tray.

Gently trace a circle in the centre of the dough with your finger, leaving a ~5cm border around the edge. Brush the area of the circle with a thin layer of egg white. Spoon the blueberry filling onto the dough and spread out to cover the circle. Gently fold the edges of the dough over the blueberry filling, gently moulding the dough back together if it cracks. Brush the pastry with more egg white and sprinkle with brown sugar to finish.

Bake for 30-40 minutes, rotating halfway through, or until the pastry is evenly golden brown and the filling is thick and bubbling. Allow to cool for a bit before serving with scoops of ice cream.

Notes: Have a look at our Peach and raspberry galette for more inspiration.