Step 1Preheat oven to 220°C (200°C fan) mark 7. Halve and stone the plums, then cut each half into 4 wedges. Halve, core and cut the apples into 5mm (1/4in) thick slices Arrange plums, apples, star anise and vanilla pod in a shallow baking tin or lipped baking tray about 23 x 33cm (9 x 13in). Scatter over sugar and bake for 10min. Meanwhile, remove pastry from the fridge.
Step 2Make the crumble. Put flour and a pinch of salt into a bowl and rub in butter with your fingers until mixture resembles fine rubble. Mix in sugar with your fingers, pinching the mixture together so you have a mix of fine and clumpy bits. Tip on to a small baking tray in an even layer.
Step 3Remove tin from oven, add blackberries and dot over the butter. Unroll pastry and lay on top of the fruit, tucking it in around the edges so the fruit is completely enclosed.
Step 4Bake tart and crumble for 15-20min or until both pastry and crumble are deep golden. Stir crumble once or twice during cooking so it browns evenly.
Step 5Leave tart to rest for 5min before inverting on to a board. Sprinkle over crumble. Serve (avoid eating star anise and vanilla pod) with ice cream, sweetened mascarpone or clotted cream.