Place the potato in a medium saucepan of water and boil for 20 minutes or until tender. Drain well and return to the saucepan.
Mash the potato with the milk. Add 2 tbsp of the fresh coriander and season well with salt and pepper. Stir to combine.
Spray a medium saucepan with low calorie cooking spray and place on a medium heat. Fry the onions for 15 minutes, stirring occasionally, or until softened and golden brown.
Add the chicken, ginger, garlic, and curry powder, and fry for 4 - 5 minutes to seal the chicken on all sides.
Add the coconut milk, stir and simmer over a low heat, uncovered, for 15 minutes.
Pre-heat the oven to 180ºC fan.
Add the almonds and simmer over a low heat for a further 15 minutes, stirring occasionally. The sauce should have thickened slightly, if not cook a little longer. Stir in the remaining 1 tbsp coriander.
Place the chicken Korma mixture in a 27 x 18 cm ovenproof dish and spread out.
Spread the potato over the top using a fork and place on a baking tray.
Place in the preheated oven for 20 - 25 minutes or until golden brown.
Remove from the oven and serve.