Hull and halve the strawberries and put into a large bowl. Add the raspberries, sugar and cornflour. Grate in the zest of the orange and add a squeeze of juice, then scrape in the vanilla seeds. Toss together and spoon into 4 small, ovenproof dishes.
For the crumble, mix the sugar, buckwheat flour and ground almonds in a bowl. Dice the butter then use your fingers to rub it in, until large crumbs form.
Sprinkle the crumble over the fruit and bake for 30 minutes, or until the topping is golden and the fruit is bubbling.