Preheat oven to 350 degrees. Place walnuts on a baking sheet and cook until toasted and fragrant, about 7-10 minutes. Set aside.
In a medium saucepan, heat the olive oil over medium heat. Add the onions and sprinkle with salt. Cook the onions for 3-4 minutes until they start to soften. Sprinkle in the curry and stir to combine. Cook the curry for about a minute until it becomes fragrant then add the apples, ginger, brown sugar, dried cranberries and water.
Cover and cook for 5-6 minutes until apples soften slightly and cranberries plump. Stir in the cornstarch and cook over medium high heat for about a minute until the syrup thickens. Remove from heat. Adjust seasonings to taste -- adding more salt or brown sugar if needed.