First-order Type-I Curry - Cooking like a Boss

A generic, tasty curry recipe which is about as quick to make as a jar curry but has actual flavour. Stolen from BBC Good Food.

oil		fry until soft	fry briefly	bring to boil	cover on medium-high for 5-6 minutes or chicken cooked	simmer and stir in
2 red onion	thinly sliced
2 clove garlic
4 tsp 0.02 l 20 ml 1 ¹⁄₃ tbsp 0.085 cup 0.035 pint ready-prepared ginger
2 tsp 0.01 l 10 ml ²⁄₃ tbsp 0.042 cup 0.018 pint ready-chopped chillies
400g ²⁄₅kg 0.882lb 14.1oz chopped tomatoes
100ml 0.1l 6 ²⁄₃tbsp 20tsp 0.423cup 0.176pint water
400g ²⁄₅kg 0.882lb 14.1oz chicken	cubed
4 tsp 0.02 l 20 ml 1 ¹⁄₃ tbsp 0.085 cup 0.035 pint garam masala
6 tbsp 0.09 l 90 ml 18 tsp 0.38 cup 0.158 pint yogurt
2 handful coriander leaves	roughly chopped