In a cup or small bowl, cover the tamarind paste with about 3 tablespoons of hot vegetable stock. Set aside for about 10 minutes. It won't dissolve completely but it will soften. Whisk with a fork to remove any lumps.
Saute the onion, garlic and pepper in a little vegetable oil for about 5 minutes, until starting to soften.
Add the mushrooms and saute for another 5 minutes.
Add the tamarind paste (with the stock it was dissolved in) and the tomato puree.
Stir well then add the borlotti beans, vegetable stock and chopped parsley.
Simmer for 15 minutes to let all the flavours blend together.
Serve with crumbled feta cheese (optional) and crusty bread.
Recipe by Veggie Runners at https://www.veggierunners.com/2013/10/07/borlotti-bean-and-tamarind-soup/