Sweet Potato & Black Bean Shepherd's Pie

WHAT YOU'LL NEED

• 600 g sweet potatoes cut into small cubes
• 1 red onion, finely chopped
• 2 garlic cloves, crushed
• ½ tbsp olive oil
• 1½ tsp smoked sweet paprika
• 1 tbsp ground cumin
• 150 g chestnut mushrooms sliced
• 400 g can dried black turtle beans, rinsed and drained
• 400 g red kidney beans, drained
• 400 g can chopped tomatoes
• 1 tbsp tomato purée
• 1 Knorr Vegetable Stock Pot
• squeeze lime juice