Vegetarian casserole

INGREDIENTS

• 1 tbsp olive or rapeseed oil
• 1 onion , finely chopped
• 3 garlic cloves , sliced
• 1 tsp smoked paprika
• ½ tsp cumin
• 1 tbsp dried thyme
• 3 medium carrots , sliced (about 200g)
• 2 medium sticks celery , finely sliced (about 120g)
• 1 red pepper , chopped
• 1 yellow pepper , chopped
• 2 x 400g tins tomatoes or peeled cherry tomatoes
• 250ml vegetable stock cube (we used 1 Knorr vegetable stock pot)
• 2 courgettes , sliced thickly (about 300g)
• 2 sprigs fresh thyme
• 250g cooked lentils (we used Merchant Gourmet ready-to-eat Puy lentils)