Creamy roasted vegetable soup with chickpeas

Ingredients

• 3 potatoes
• 1/2 sweet potato
• 2 carrots
• 1 onion
• 1 leek
• 1 head of garlic
• 2 1/2 cm piece of ginger
• 1/2 bunch of coriander
• 3 tbsp olive oil
• 1 tsp ground cumin
• 1 l of vegetable stock
• 200 ml tomato passata
• 2 tbsp Kikkoman Ponzu Citrus Seasoned Soy Sauce - Lemon
• 1/2 tsp of mixed pepper
• 100 g cooked chickpeas
• 50 g celeriac
• 2 tbsp sour cream