Heat the oil in a big pot.
Add the sliced onions.Cook on med-low heat, stirring often, till they are soft, light brown, and slightly mushy.
Once the onions are ready, add the curry leaves, cumin, fennel , mustard, ginger, garlic & green chili. Also add the dry ground spices- pepper, chili powder, coriander powder, salt & turmeric
Give it a mix and saute for about 20-30 seconds.
Add the chopped tomatoes and cook at medium flame for 15-20 minutes, till the tomato is mushy and mixes with the rest of the masala.
Keep sautéing the masala till you get a jammy consistency of the onions and tomato. Add 2-3 tablespoons of water if the onions and tomatoes are burning.
Use a heavy ladle or potato masher to lightly mash the onion-tomato base sauce.
Take off the heat.Add boiled eggs- whole or halved.
Garnish with coriander and serve with parathas or rice.