Mix the flour, sugar and salt in a bowl. Add the butter and rub together using your hands to form an even, crumbly mixture. Add the water, mix quickly to create a soft dough (do not knead), cover and refrigerate for approx. 30 mins. Roll out the dough on a sheet of baking paper (approx. 30 cm in diameter), place on a baking tray.
Mix the strawberries with the vanilla sugar and sugar, spread on top of the dough leaving a border of approx. 4 cm. all around. Fold the dough inwards around the edge, brush with egg white and sprinkle with sugar.
Approx. 45 mins. in the lower half of an oven preheated to 180°C. Remove the galette, leave to cool, serve with double cream.