Preheat oven to 200C and grease and line a baking tray with baking paper.
Roll out pastry to a large square, and place on tray.
Combine the ricotta and orange rind in a medium bowl then spread across pastry, leaving a 5cm border.
Toss strawberries, rhubarb, caster sugar and vanilla in a medium bowl to combine. spread fruit over the top of the ricotta, then fold over the pastry edges, pressing the corners together lightly to seal. Brush the pastry edge with the beaten egg, and sprinkle with raw sugar. Place in fridge for 10-15 minutes to firm.
Bake for 10 minutes, then reduce the heat to 180C and bake for a further 40 minutes until filling bubbles and pastry is golden brown. Allow to cool for 10 minutes before serving.