Put the berries and granulated sugar into a saucepan – NOT an aluminium pan – over a moderate heat, with the lid on the pan. Shake the pan gently from time to time as the berries soften and release their juices, which they will.
When they are soft and the sugar is dissolved, take the pan off the heat and tip the contents into an ovenproof dish. Cool.
Meanwhile, to make the crumble melt the butter in a wide saucepan, and stir in the Demerara sugar and vanilla extract, and cook, stirring, on a moderate heat for 3-4 minutes.
Then stir the Nairn’s Porridge Oats into the contents of the pan, and continue to stir thoroughly. Spoon this over the cooled fruit, evenly.
Bake in a moderate oven, 350’F 180’C gas 4 for 25-30 minutes, or until the surface is golden brown with the fruit bubbling gently round the edges.
Take the dish from the oven, and serve warm, rather than hot from the oven
1 ½ lbs/675g berries - these can be blueberries, raspberries, strawberries, blackcurrants, blackberries (brambles) or a combination, depending on what's in season
4 oz./120g golden granulated sugar
For the crumble:
2 oz./55g butter
2 oz./50g Demerara sugar
2 oz./50g rolled, Nairn's Porridge Oats or crushed Nairn's Oatcakes
½ tsp vanilla extract