Heat oil in a deep pan. Add cumin seeds, mustard seeds. Once it starts crackling, add red chilies and curry leaves in to it. Saute it for few sec. Add Asafoetida (hing) and chopped garlic and ginger. Saute it for about 40 seconds till garlic and ginger gets slightly golden color. Add onion and little salt and saute it at medium heat for 5-6 min till onion gets slightly golden color. Add boiled and cut tomatoes, stir it well and cook at medium to high heat with covered lid.