In a large heavy pot, heat 2 tbsp oil on medium-high heat and saute the onions for 2-3 minutes until translucent. Add the beef chunks, turmeric, garlic powder, onion powder, salt, and pepper. Brown all sides and add the marrow bones and continue stirring - about 5 minutes.
Add the potato chunks, tomato sauce, sour grapes/ lime juice, beef broth and just enough water to cover the meat and other ingredients, bring to boil, then reduce heat and let simmer for about 1.5 - 2 hours.
Sprinkle the eggplant with a bit of salt. In a large pan, heat 1/2 of the oil on medium-low and allow the eggplant to cook, regularly turning them so the color is consistent. As the oil gets absorbed, gradually add more oil and cook until the eggplant is light brown on all sides - add more oil if required. Remove to parchment-lined plate.
When meat is cooked for about 1.5 - 2 hours, lay the eggplants on top of them in the pot and gently press them down to submerge. Cook for an additional 1.5 - 2 hours and then serve on rice, fries or on its own.