To begin, preheat your oven to 190°C (170°C fan). Lightly butter a medium baking dish to prevent sticking. Transition to preparing the rhubarb filling.

Place the chopped rhubarb into a large mixing bowl. Add caster sugar, flour, and ground ginger if using. Toss gently to coat the fruit evenly. Transfer the mixture into the prepared baking dish.

In another bowl, combine plain flour, rolled oats, light brown sugar, and a pinch of salt. Stir well to distribute ingredients evenly. Proceed to work in the butter.

Add cold cubed butter to the dry mix. Using your fingertips, rub until the mixture resembles coarse breadcrumbs with some larger oat clusters for texture. Move to assembling the crumble.

Scatter the crumble mixture evenly over the rhubarb, covering the fruit completely. Press down lightly without compacting too firmly to maintain a light and crisp texture. Transition to baking.

Place the dish in the preheated oven and bake for 35–40 minutes until the topping is golden brown and the fruit is bubbling at the edges. Check halfway and rotate for even colouring. Move to cooling before serving.

Allow the crumble to rest for 5–10 minutes before serving. Pair with custard for traditional comfort or serve with double cream or vanilla ice cream for a richer finish. Presentation tip: Dust lightly with icing sugar just before serving.