Wash the chicken breast fillets and pat dry. Remove skin if necessary. Cut into strips with a sharp knife.
Peel the garlic cloves and ginger, then finely chop both.
Heat a dry pan over medium heat and roast the cashew nuts for 3 minutes until light brown. Set aside.
Cook the basmati rice in salted water over medium heat for 25 minutes.
Heat the sesame oil in a deep pan over medium-high heat. Fry the chicken, garlic, and ginger for 4 minutes.
Add the tomato paste and fry for 1 minute. Pour in the vegetable stock and add the red curry paste. Stir and simmer over medium heat for 5 minutes.
Wash the tomatoes, cut into cubes, and add to the curry. Continue simmering over medium heat until the chicken reaches an internal temperature of 74°C (165°F).
Squeeze the lemon. Season the curry with lemon juice, salt, and pepper to taste.
Wash the coriander greens, shake dry, pluck the leaves from the stems, and roughly chop them. Stir the chopped coriander and toasted cashew nuts into the curry. Serve immediately with the rice.