Take the fillo pastry out of the fridge and let it come to room temperature in its packaging.
Preheat your oven to 180 degrees Celsius or 350 degrees Fahrenheit.
In a bowl, whisk together cream, sugar, eggs, vanilla, and lemon zest. Set aside.
Place one sheet of fillo pastry on your workspace with the short side facing you. Brush with melted butter and layer another sheet on top. Fold the pastry in a concertina design and transfer it to a 12-inch round baking tray. Coil it in the middle to create a rose shape. Repeat with the remaining fillo pastry until the tray is full.
Brush the fillo pastry with the remaining melted butter and bake for about 15 minutes or until lightly golden. Pour the custard over the baked pastry and scatter blueberries on top, pressing some into the pastry.
Return the tray to the oven and bake for another 30 minutes or until golden. Remove the pastry from the oven and let it cool for 10 minutes before dusting with powdered sugar. Enjoy your Lemon & Blueberry Pastry!