1. Preheat the oven to 350°F (180°C). Lightly grease a 9 inches (23cm) pie dish or casserole dish and set aside.

2. Wash, dry, halve and pit the damson plums. Place in a bowl. Add sugar, cornstarch, lemon zest, cinnamon, and lemon juice, and mix well. Transfer to the prepared baking dish.

3. For the crumbles, mix the flour, porridge flakes, sugar, cinnamon, and salt in a bowl. Add the cold butter in small pieces. Rub everything between your fingers until you get nice crumbles of different sizes. Distribute evenly over the plums and bake in the preheated oven for about 45-50 minutes. The crumbles should have a nice color and the liquid from the plums should be bubbling here and there at the surface of the crumble. Remove from the oven and let cool slightly. The Damson Plum Crumble tastes best served still warm with some whipped cream/ice cream/vanilla sauce ;)