For the massaman curry paste, heat a small frying pan over a medium heat. When the pan is hot, add the cardamom seeds, cumin seeds and cloves and dry-fry for 1-2 minutes, or until fragrant.
Transfer the spices to a spice grinder or pestle and mortar and grind to a powder.
Blend the ground spices with all of the remaining massaman curry paste ingredients in a food processor, until smooth and well combined. (Alternatively, pound the paste until smooth in a pestle and mortar.) Chill until needed, covered.
To make the chicken curry, heat the oil in a medium-sized, flameproof, lidded casserole. Add the onions and fry for 8-10 minutes, or until softened and light golden-brown.
Increase the heat, push the onions to one side of the casserole, then add the chicken strips to the other side and fry for 2-3 minutes on all sides, or until sealed all over.
Add half of the massaman curry paste to the casserole (see tip). Stir well to coat the chicken and onions in the paste. Fry the mixture for 1-2 minutes, or until fragrant.
Add the potatoes, chillies, chicken stock, coconut milk, tomatoes, lime leaves, fish sauce, palm sugar and soy sauce to the casserole. Stir well and bring the mixture to the boil, then cover the casserole with the lid and reduce the heat until the mixture is simmering. Continue to simmer for 12-15 minutes, or until the chicken is cooked through (do not overcook the chicken as it will become dry). Season, to taste, with a little more fish sauce or some lime juice.
Just before serving, stir in the basil leaves and half of the peanuts.
To serve, spoon the Thai massaman curry into bowls and garnish with the extra Thai basil leaves, the sliced red chilli, and the remaining peanuts. Serve with steamed sticky rice.