For the curry paste: Combine all the ingredients in a small bowl and whisk together.
Place the onion, garlic and ginger in a slow cooker (5 litre capacity). Add the chicken pieces and then the paste. Stir well to combine. Cook on high for 4 hours.
1 brown onion, 3 cloves garlic, 3 cm ginger piece, 1 kg chicken thighs, 3 tablespoons tomato paste, 2/3 cup chicken stock, 2 teaspoons curry powder, 2 teaspoons garam masala, 1 teaspoon ground turmeric, 1 teaspoon sea salt, 1/2 teaspoon cracked black pepper
After 3 hours, add the zucchini and cauliflower, if using. Stir well.
2 zucchini, 1 cup cauliflower florets
After 4 hours, turn off and add the greek yoghurt, lime juice, brown sugar and spinach (if using). Stir well to combine.
3/4 cup greek yoghurt, 1/2 lime, 1 1/2 teaspoons brown sugar, 2 cups baby spinach
Serve on rice with toasted roti or naan bread and fresh coriander.