Warm the vegetable oil in a wide skillet over medium-high heat, then sprinkle in the curry powder. Let it toast for about 5 minutes, stirring often so it doesn't catch and burn.
Toss in the sliced onion and let it soften for roughly 4 minutes, until it turns translucent. Stir through the crushed garlic along with the salt, pepper, and paprika, cooking for another minute to release the aromas.
Fold the diced chicken into the pan so every piece gets coated in the spice mix. Pour in the stewed tomatoes, coconut milk, brown sugar, and grated ginger, then stir well and bring everything up to a gentle simmer. Leave it uncovered to bubble away for around 35–40 minutes, stirring now and then, until the sauce reaches your preferred thickness.
Turn off the heat and mix in the fresh lime juice, shredded coconut, and crushed cashews for a final layer of flavor and texture.
Spoon the curry generously over warm jasmine rice. Top with green onions or cilantro, plus extra coconut and cashews if you like a bit more crunch.