Heat 2 tablespoons of oil in a large pan over medium heat. Add the onion and cook for 3-4 minutes until soft. Add the garlic, ginger, and chilli, and cook for another 30 seconds until fragrant. Stir in the curry powder and turmeric and cook for 1 minute to toast the spices.
Add the tomatoes and cook for 2-3 minutes until softened and jammy. Add the chicken and stir to coat in the spice mix. Cook for another 2-3 minutes until the chicken starts to colour.
Next, add the pumpkin, coconut milk, chicken stock, soy sauce, and sugar. Stir well, bring to a simmer, then cover and cook on low heat for 20-25 minutes, until the pumpkin is tender and the chicken is cooked through.
Let the curry continue to simmer until slightly thickened or stir in the cornstarch slurry and cook for 1-2 minutes until thickened, glossy and rich.
Taste and season with salt if needed. Serve with fresh coriander, jasmine rice or roti, and a drizzle of chilli oil for extra heat – and don't forget the Gewürztraminer.
