1. Preheat the oven to 190C (170C fan)
2. To make the fruit filling, place the pears into a large bowl with the sugar, lemon juice and cardamon and set aside for a few minutes whilst you make the crumble topping.
3. Place the sugar, oats, cinnamon, ground and chopped California walnuts into a bowl and mix together evenly. Drizzle in the oil as you stir with a fork, forming clumps of crumble mixture.
4. Sprinkle the cornflour over the fruit mixture and stir to combine. Scrape the fruit mixture into a large ovenproof dish and sprinkle over the crumble topping. Bake in the oven for about 40 minutes or until the juice of the fruit is bubbling and the topping is crisp.
5. Serve warm with a little cream
Recipe courtesy of California Walnuts