- Pre-heat the oven to 350 degrees.
Place a sauce pan over medium heat and add the entire jar of cherry jam, kudzu starch mixture and the remaining reserved cherry juice. Cook for 5-7 minutes stirring frequently until thickened.
Pour the thickened mixture over the drained sour cherries and give it a mix. Spread the mixture into an 8 x 9-inch baking dish and set aside while you make the crumble mixture.
Add the chopped hazelnuts, brown butter, jaggery, oat flour, roasted hazelnut flour and salt into a mixing bowl. Combine with your fingers or a pastry cutter until coarse crumbles and pea sized clumps form.
Top the cherry mixture with the hazelnut crumble mixture and place in the oven. Bake for 50-60 minutes until the top is golden brown and the filling is bubbling.
Serve warm with vanilla bean whipped cream or ice cream.