Fijian creamy lentil soup with caramelised onion

Ingredients

• 375g (1 1/2 cups) red lentils
• 1 litre (4 cups) vegetable stock or water
• 1/2 tsp ground turmeric
• 2.5cm piece ginger, peeled and chopped
• 2 tomatoes, chopped
• 250ml milk
• 1 tsp sea salt
• 60g unsalted butter
• 1 brown onion, diced
• 1 tsp cumin seeds
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