1 garlic clove, crushed
1.25cm/陆in piece fresh ginger, peeled
1 tbsp chopped lemongrass
2 limes, zest and juice
1 onion, peeled and finely chopped
675驳/1陆濒产 sweet potatoes, peeled and diced
1 x 400ml tin coconut milk
salt and freshly ground black pepper
1 tbsp groundnut oil
570ml/1 pint vegetable stock