Spicy pumpkin and lentil tagine

Ingredients

• 1 tbsp sunflower oil
• 1 brown onion, finely chopped
• 3 garlic cloves, crushed
• 1 tsp ground cumin
• 1 tsp ground sumac
• 1 tsp ground coriander
• 1⁄4 tsp ground chilli (optional)
• 420g can low salt diced tomatoes
• 1 tbsp tomato paste
• 1⁄2 tsp sugar
• 1⁄4 cup flat leaf parsley, chopped
• 1⁄4 cup coriander leaves, chopped
• 400g can brown lentils (drained and rinsed)
• 600g butternut pumpkin, seeded and chopped into 2cm pieces