Step 1

Heat oven to 220C/fan 200C/gas 7.

Step 2

In a bowl, mix together 2 tbsp olive oil and 1 tsp coriander seeds, 1 tsp cumin seeds, ½ tsp ground turmeric and ½ tsp mustard seeds.

Step 3

Add 1 large onion, cut into 8 chunks, 2 garlic cloves, 675g parsnips, diced, and 2 quartered plum tomatoes and mix well.

Step 4

Spread over a heavy baking sheet, then roast for 30 mins until tender.

Step 5

Spoon into a food processor or liquidiser with 600ml vegetable stock and process until smooth.

Step 6

Pour into a pan with the remaining  600ml vegetable stock, season, then heat until barely simmering.

Step 7

Remove from the heat and stir in 1 tbsp lemon juice. Garnish with cumin seeds.