Spiced parsnip & cauliflower soup

Name: Spiced parsnip & cauliflower soup
Prep time: 15 min
Cook time: 50 min
Total time: 1 h 5 min
Cuisine: British
Ingredients: 1 tbsp olive oil; 1 medium cauliflower , cut into florets; 3 parsnips , chopped; 2 onions , chopped; 1 tbsp fennel seed; 1 tsp coriander seed; ½ tsp turmeric; 3 garlic cloves , sliced; 1-2 green chillies , deseeded and chopped; 5cm piece ginger , sliced; zest and juice 1 lemon; 1l vegetable stock; handful coriander , chopped