The crumble topping is an old favourite of mine, it’s almost flapjack-like, as I make the crumble mixture, bake it first and then place it on top of the fruits and bake it for a second time. I dislike a soggy crumble, hence I find that the twice-baked crumbles deliver not only a fantastic baked-cum-roasted taste, they deliver on texture too.
I use a cherry stoner to remove the stones from the small wild plums and it works a treat.
For the oat and hazelnut crumble
150g plain flour
150g soft dark brown sugar
a pinch of table salt
1 teaspoon ground cinnamon
150g unsalted butter, diced
150g jumbo or porridge oats
80g hazelnuts, chopped
For the wild plum filling
800g wild plums (use one type or a selection, such as bullaces, damsons, mirabelles, greengages), stones removed, then plums left whole if small, otherwise cut in half
200g soft dark brown sugar
1 teaspoon ground cinnamon
100g ground almonds
100g fresh breadcrumbs
For the vanilla custard
300ml full-fat milk
150ml single cream
1 vanilla pod, split in half lengthways and seeds scraped out
8 egg yolks
60g caster sugar
First, prepare the oat and hazelnut crumble. Preheat the oven to 180°C/Gas Mark 4 and line a baking tray with non-stick baking paper. Place the flour, brown sugar, salt, cinnamon and butter in a mixing bowl, then use your fingertips to rub the butter into the flour mixture until the mixture resembles coarse breadcrumbs. Stir in the oats and chopped hazelnuts, then transfer the crumble mixture to the prepared baking tray and spread it out evenly. Bake in the oven for about 20 minutes or until light golden and semi-crisp, stirring it once during cooking.
Remove from the oven and leave the mixture to cool on the baking tray for about 1 hour. Bits of the crumble will have stuck together, almost like flapjacks, so break these up into crumb-size pieces using your fingers. Once cold, the crumble mixture can be transferred to an airtight container and kept in the fridge for up to 1 week (it will lose a little of its crispness during storage, but once it is baked for the second time, it will crisp up again and be perfect).
For the wild plum filling, preheat the oven to 180°C/Gas Mark 4. Place all the ingredients for the filling in a large mixing bowl and mix them together using your hands. Select your ovenproof serving dish or dishes – use either one large oven-to-table dish or 6 individual dishes (I often use cast iron skillets to make individual crumbles, each skillet measures about 12cm diameter by 3.5cm high). Spoon the fruit mixture into the dish or dishes and then bake in the oven for 15 minutes or until the mixture has thickened and the fruit has collapsed.
Remove from the oven. Cover the fruit mixture with the crumble mixture crumbs, then return to the oven and bake for a further 10–12 minutes or until the crumble topping has crisped up and turned golden brown.
While the crumble is baking, make the custard. I usually use my Thermomix for making custard, but from time to time, I also revert back to the conventional method. Either way works perfectly (see Cook’s Tip for the Thermomix method). Rinse a medium saucepan with cold water, then put the milk, cream and vanilla seeds in the pan and cook gently over a low heat until the milk starts to boil.
While the milk mixture is heating, lightly whisk the egg yolks and caster sugar together in a heatproof bowl. Add a ladleful of the hot milk to the egg mixture and whisk in, then pour the egg mixture into the remaining hot milk in the pan, stirring. Cook over a low heat, stirring continuously, for 7–8 minutes or until the mixture cooks and thickens enough to coat the back of the wooden spoon. Do not allow to boil or the custard may curdle. Remove from the heat and pour the custard into a serving jug. Serve warm with the hot baked crumble.
To make the egg custard using the Thermomix method, place all the ingredients for the custard in the Thermomix jug. Blend for 30 seconds on speed 8, then insert the butterfly whisk and set the timer for 12 minutes at 80°C on speed 4. Check if the custard is cooked, looking for the characteristics as described in the main recipe above; if it’s not quite cooked enough, cook for a further 3 minutes at 80°C on speed 4. Pour the custard into a serving jug and serve with the hot baked crumble.