Place the rice in a pan with 700ml of boiling water and a pinch of salt. Bring to the boil, then cover and reduce the heat to low. Simmer for 15 minutes until tender. Set aside.
Put the minced lamb into a large bowl with the egg, breadcrumbs, ½ the diced red onion, coriander, and a teaspoon of the curry paste. Peel and crush in the garlic and season with salt and pepper, then mix to combine. Shape into 16-18 even-sized balls.
Heat a large non-stick frying or sauté pan over a medium to high heat. Add half the oil and sauté the meatballs for 10 minutes until lightly golden. Transfer to a plate.
Add the rest of the oil to the frying pan over a medium heat and add the remaining red onion, ginger, red pepper, yellow pepper and the remaining five teaspoons of the curry paste. Sauté for 2-3 minutes and then add the tomatoes and continue to cook for 3 minutes. Stir in the coconut milk and bring to the boil, then reduce the heat and simmer for 5 minutes.
Add the meatballs back into the sauce. Reduce the heat to low and simmer for 8-10 minutes until the meatballs are completely tender. Just before serving, squeeze in the juice of half the lemon and arrange on plates with the rice. Spoon a small amount of yoghurt on top and scatter over the toasted flaked almonds.