Heat oven to 200C/fan 180C/gas 6. Prepare the Roasted rhubarb adding the halved strawberries after 15 mins of cooking. Cook, uncovered, for a further 5 mins until the rhubarb is tender and the strawberries slightly softened. Tip into a shallow dish, about 25 x 18 x 5cm, with enough of the syrupy juices to keep the fruit juicy. (Any leftover can be served with the crumble.)
While the fruits are roasting, prepare the crumble. Mix the flour, sugar and ground almonds, then add the butter and rub together to make coarse crumbs. Stir in the orange zest.
Spoon the crumble loosely over the fruit, then scatter with the pine nuts. Bake straight away for 25 mins until golden and bubbly. Cool a little before serving with custard and any remaining syrup.