Potato Basil Soup with Tempeh

For the soup:
1 tablespoon oil
150 g (1 1/2 cups) celeriac, finely cubed
1 medium onion, chopped
1 tablespoon chopped ginger
3 cloves garlic, minced

1 kg (2 lb 3 oz) waxy potatoes, peeled and cubed
1200 ml (5 cups) vegetable broth
1 tablespoon dried tarragon
120 g (1/2 cup) plain soy yoghurt
15 g (1/2 cup packed) fresh basil
salt, pepper, and lemon juice to taste

For the tempeh:
150 g tempeh, cubed
3 tablespoons soy sauce
2 tablespoons worcestershire sauce
60 ml (1/4 cup) water
1 teaspoon oil

Heat oil in a large pot. Add celeriac, onion, ginger, and garlic. Fry over medium heat until the onions are brown, about 15 minutes. Deglaze the pot with several tablespoons of water, if necessary.

Add potatoes, vegetable broth,  and tarragon. Cook over medium heat until potatoes are soft, about 25 minutes.

Meanwhile prepare the tempeh. Combine soy sauce, worcestershire sauce, and water in a bowl.  Add tempeh and mix well. Let sit for 20 minutes, stirring from time to time.

Drain tempeh and reserve the marinade. Heat 1 teaspoon of oil in a pan. Fry tempeh until crispy. Add 1 tablespoon of marinade if the tempeh sticks to the pan.

Remove soup from heat. Stir in yoghurt and basil. Purée the soup and add 3-4 tablespoons of tempeh marinade. Season with salt, pepper, and lemon juice. Pour into soup plates or  bowls and add tempeh. Serve immediately.