Sweet and buttery, parsnips are one of winter's gifts to help us through the first frost. Try this wonderful spicy soup and side, inspired by Emma, my chef at Whitechapel gallery.

The soup

25g butter

1 tbsp olive oil

1 small onion, finely sliced

4 medium parsnips, peeled and finely sliced

2 tsp curry powder

300ml vegetable stock or water

50ml double cream

Put the butter and olive oil into a pan. When it warms, add the onion and saute for two minutes. Before the colour changes, add the parsnips and curry powder and continue to fry for five minutes. Cover with the stock or water, simmer for 15 minutes or until the parsnips are soft. Blend the contents into a smooth soup and return to the pan. Then add the cream, bring to the boil and season. If it's too thick, add some stock or milk.

The bhaji

1 medium onion, finely sliced

30g plain flour

Pinch coriander powder

Pinch cumin powder

1 egg, beaten

200ml vegetable or groundnut oil

Put the sliced onion in a bowl with the flour and spices and mix together. Add the egg, season, and mix well. Heat the oil in a deep pan and add a large spoonful of the bhaji mix. Fry for one minute, turning occasionally until golden brown. Drain on to kitchen paper and serve with the soup.

• Angela Hartnett is chef patron at Murano restaurant and consults at the Whitechapel Gallery and Dining Room, London. Twitter.com/angelahartnett