Chicken, lentil and pumpkin curry

Ingredients

• 2/3 cup (130g) dried brown lentils
• 2/3 cup (130g) dried red lentils
• 1 tablespoon vegetable oil
• 1 large brown onion (200g), chopped finely
• 2 cloves garlic, crushed
• 2 1/2 centimetre (1 inch) piece fresh ginger (10g), grated
• 2 teaspoons ground cumin
• 2 teaspoons ground coriander
• 2 teaspoons black mustard seeds
• 1 teaspoon ground turmeric
• 1 fresh long red chilli, chopped finely
• 3 cups (750ml) chicken stock
• 1 kilogram (2 pounds) chicken thigh fillets, chopped coarsely
• 400 grams (14½ ounces) canned diced tomatoes
• 500 grams (1 pound) pumpkin, chopped coarsely
• 1 1/4 cup (270ml) canned coconut milk
• 155 grams (5 ounces) baby spinach leaves
• 1/2 cup coarsely chopped fresh coriander (cilantro)