Soak lentils, chickpeas and beans in the water overnight. In the casserole, fry the onion with oil until it turns yellow. Add the bulgur, then the tomato paste and stir. 

Add lentils, chickpeas, beans and broth.

Then add the peppers and keep the lid closed until it boils and cook over low heat.

Cook for about an hour until beans and chickpeas are tender. After adding the salt, cook for another ten minutes and take it off the stove. 

Let rest for 15/20 minutes and serve.