To make the curry paste, halve, deseed and roughly chop the chilli(es), then peel the garlic and ginger.
Place a frying pan over a medium-high heat and scatter in the cumin and coriander seeds. Lightly toast for a few minutes, or until golden brown and smelling delicious, then remove from the heat.
Add the toasted spices to a pestle and mortar and grind until fine, or whiz to a powder in a food processor.
Once ground, add the toasted spices to a food processor along with the remaining paste ingredient and ½ teaspoon of sea salt, then whiz to a smooth paste. Put aside.
Slice the chicken lengthways into 2cm strips.
On a clean chopping board, peel, halve and finely slice the onions. Peel and finely slice the ginger, then pick the coriander leaves and put to one side, finely chopping the stalks along with the chilli.
Heat 2 tablespoons of oil in a large casserole pan over a medium-high heat, add the onions, chilli, ginger and coriander stalks, then cook for around 10 minutes, or until softened and lightly golden.
Add the chicken and 140g of the tikka masala paste, stirring well so everything is nicely coated. Season with salt and black pepper, add the tomatoes, breaking them up with the back of a spoon, and the coconut milk, then bring to the boil.
Turn the heat down to medium-low, cover and simmer for 20 minutes, then remove the lid and cook for a further 5 minutes, or until the meat is tender and the sauce has reduced, stirring occasionally.
Divide the curry between bowls, sprinkle over the almonds and coriander leaves. Add a dollop of yoghurt and a wedge of lemon to each bowl. Delicious served with fluffy rice.