Heat oil in a wok and add cumin seeds, green chilli and chopped garlic and saute for a min.
Add chopped onions and saute till they are light brown and then add diced sweet potato and mix well with little salt and cumin powder and let it cook till its sides are light brown.
Puree blanched spinach with little green chilli and couple of garlic cloves.
Mix the spinach puree with sweet potato and cook them on slow flame.
At the end just add little gram masala and lemon juice and mix well.
Heat a little ghee and add garlic and then temper the spinach from top.