Shrimp Balls

These shrimp balls accompanied by a spicy tamarind and tomato sauce are served as an appetizer, or as an accompaniment to rice. White fish fillet may be used instead of shrimp.
2 pounds uncooked shrimp, peeled, deveined, and drained
1â„4 cup fresh cilantro, chopped
3â„4 tsp turmeric powder
1 tsp salt
3â„4 cup rice flour
4 TBS ghee (clarified butter, available from Indian and Middle Eastern stores; or substitute melted, cooled butter)
2 onions, chopped fine
2 tsp baharat powder (a spice blend available in Middle Eastern stores; or mix 1â„2 tsp paprika, 1â„4 tsp each nutmeg, black pepper, coriander, cumin, cloves, cinnamon, and a pinch of cardamom)
2 TBS grated lemon rind
1 2-inch piece tamarind (or juice of 1â„2 lemon)
2 cups warm water
1 cup fresh or canned chopped tomatoes
1â„4 tsp chili powder
1 tsp sugar

In a food processor, process the shrimp to a paste with cilantro, turmeric, salt, and rice flour. Transfer to a covered dish and refrigerate until needed.
Heat 2 tablespoons ghee. Saute onions until softened. Reserve one half of the onions for later use in the sauce.
To prepare the spiced onion filling: to the remaining onions in the pan, stir in 1 teaspoon baharat and rind. Cook for 1 minute. Remove from heat, and reserve.
Soak tamarind in 1 cup warm water for 15 minutes. Remove seeds by kneading the pulp with fingers. Pass the tamarind through a sieve, pressing with a spoon to extract all the juices. Discard the solids.
To prepare the sauce: In a saucepan, add the reserved fried onions.
Heat remaining 2 tablespoons ghee. Saute onion until transparent.
Stir in the tamarind liquid, remaining 1 cup warm water, 1 tsp baharat, tomatoes, chili powder, and sugar.
Cover and simmer gently for 15 minutes.
Meanwhile, prepare the shrimp balls.
Moisten your hands with water to prevent the paste from sticking to them.
Take 1 tablespoon of the shrimp mixture, and form into a ball.
Make a cavity with your thumb in the center, and fill with 1 teaspoon of the spiced onion.
Firmly press the shrimp paste around the filling to seal well.
Repeat with the rest of the ingredients, and remember to moisten your hands with water before rolling.
Slip the shrimp balls into the simmering sauce.
Cover and cook over low heat for about 20 minutes