Step 1
Preheat the oven to 200°C/fan oven 180°C/Gas Mark 6.

Step 2
Mix the plums with the sugar, orange zest, orange juice and cinnamon. Tip them into a 1 litre (1 ¾ pint) ovenproof dish.

Step 3
Put the flour, porridge oats and salt into a mixing bowl and add the Trex, rubbing it in with your fingertips until the mixture looks like crumbs. Stir in the sugar, ground almonds and flaked almonds. Sprinkle the topping evenly over the fruit, then bake for 25-30 minutes, until golden brown.

Step 4
Serve the crumble with single cream, ice cream or custard.