Can someone help me with my tomato stew

Here's the recipe:

7 canned tomatoes - 2 tbs of tomato paste - 4 big size onions - Sunflower oil - 3 thumbs of ginger - 5 cloves of garlic - 1 tbs of Anniseseed - 1tbs of rosemary - 1tbs of coriander seeds - 1 tbs of grains of selim 2 tsp of curry powder Few bay Leaves 1 and half tsp of powdered pepper. - 2 tsp salt -

My problem is how bitter it is. Every time I either have to consume 2 servings before I get used to it, and/or I have to slow cook it for hours for the bitterness to die down. Is there any edits I need to do on the recipe or is the former the agreed way?