1.Heat half the oil in a 6-litre (24-cup) pressure cooker; cook lamb, in batches, until browned all over. Remove from cooker.
2.Heat remaining oil in cooker; cook onion, garlic and chilli, stirring, until onion softens. Add spices; cook, stirring, until fragrant. Return lamb to cooker with tomatoes and stock; secure lid. Bring cooker to high pressure. Reduce heat to stabilise pressure; cook 25 minutes.
3.Release pressure using the quick release method (see below); remove lid. Stir in spinach and coriander; season to taste.
If you have an electric pressure cooker you won’t need to reduce the heat to stabilise pressure, your cooker will automatically stabilise itself. Always check the manufacturer’s instructions before using. Each time the lid is removed from the cooker, the pressure must be released quickly first. Use tongs (steam can burn your fingers) to turn the pressure valve on top of the cooker to open the valve and release the steam. We use this method when adding ingredients and when checking the food toward the end of cooking time. Pack into freezer-proof containers, leaving a 2.5cm space to allow for expansion. Seal, label and freeze for up to 3 months. Thaw overnight in the fridge. Reheat in a saucepan or microwave on medium power (50%) until heated through.