Heat the oil in a pan and gently cook the onion until soft.
Stir in the garlic, ginger, and curry paste, cooking for another minute.
Add chicken pieces and coat them well with the spices.
Transfer everything into the slow cooker or instant pot.
Pour in coconut milk and chicken stock, then stir in ground almonds and tomato puree.
Cover and cook on low for 6 hours (slow cooker) or 20 minutes (instant pot, manual high pressure).
Season with salt and pepper before serving.
Garnish with fresh coriander and serve with basmati rice.