225ml double cream, plus extra to serve (optional)
Preheat the oven to 190°C, gas mark 5. Put the apples, pears, cinnamon and sugar in a large pan with a splash of water. Set over a medium heat and cook for 3-5 minutes, or until the fruit starts to soften. Stir in the lemon zest and leave to cool.
Meanwhile, prepare the topping. Mix the flour, oats, sugar and a pinch of salt in a bowl. Rub in the butter with your fingertips until the mixture resembles breadcrumbs, leaving some larger chunks for texture.
Toast the flaked almonds in a frying pan until golden. Leave to cool slightly, then stir through the oat mixture.
Transfer the fruit to a 20-23cm diameter ovenproof dish. Spread out in an even layer then scatter over the topping. Bake the crumble for 20-25 minutes, or until the topping is lovely and golden brown. Leave to cool for 5-10 minutes before you serve.
Meanwhile, make the sauce. Set a small pan with the sugar, cream and butter over a low heat. Once the sugar has dissolved, increase the heat and bring the mixture to the boil, stirring continuously for 3 minutes until caramel in colour and slightly thickened. Remove from the heat, stir in a pinch of sea salt and set aside until needed.
Serve the crumble with the caramel sauce and extra cream on the side, if you like.