Heat the oven to 180C/160C fan/gas 4. Put the flour, oats, cinnamon and the butter in a bowl. Rub the butter into the dry ingredients with your fingers to create a crumbly texture, then stir through the sugar and drizzle the golden syrup over the top. Stir again with a cutlery knife until combined, then squeeze small handfuls together in your palm to create some clumps, like a loose rubble.

Sprinkle the crumble over a baking tray lined with baking parchment and bake for 15 mins, stirring and roughly breaking up halfway through cooking. This can be done up to two days ahead and kept stored in an airtight container.

Meanwhile, prep the fruit. Put the apples, lemon juice, vanilla and 75g sugar in a large pan. Stir together and set over a medium heat. Cook until the apples just start to soften, about 4 mins, but this will really depend on the apples so do keep an eye on them. Taste some of the juices and add more sugar if the apples need it, then take off the heat. Toss the berries in the cornflour, then stir them into the apples. Transfer to an ovenproof baking dish.

Sprinkle the crumble topping over the fruit and bake for 15-20 mins until the juices are bubbling and the crumble topping is golden brown. Leave for 5 mins before serving with cold cream, ice cream, or custard.