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
4 red onion	thinly sliced
4 clove garlic
8 tsp 0.04 l 40 ml 2 ²⁄₃ tbsp 0.169 cup 0.07 pint ready-prepared ginger
4 tsp 0.02 l 20 ml 1 ¹⁄₃ tbsp 0.085 cup 0.035 pint ready-chopped chillies
800g ⁴⁄₅kg 1.76lb 28.2oz chopped tomatoes
200ml ¹⁄₅l 13 ¹⁄₃tbsp 40tsp 0.845cup 0.352pint water
800g ⁴⁄₅kg 1.76lb 28.2oz chicken	cubed
8 tsp 0.04 l 40 ml 2 ²⁄₃ tbsp 0.169 cup 0.07 pint garam masala
12 tbsp 0.18 l 180 ml 36 tsp 0.761 cup 0.317 pint yogurt
4 handful coriander leaves	roughly chopped