Wash okra and pat them with a towel to dry. Trim the tops off. Put a slit down the middle, turn it halfway and put another slit so the okra opens up. Top should be intact. Place in a large bowl.
For the paste, grind the garlic and ginger in a food processor or blender with a little water. Add the spices and process until smooth. Scrape the sides down in between if necessary, so the mixture is even.
Put the paste in a bowl and add 1 tbsp vegetable oil. Mix it up. Rub the paste all over the okra. Put some inside the slits. Cover and set aside for 30 minutes.
It’s best to cook the okra in a single layer. Heat up a large pan and add 4 tablespoons oil. When the oil is hot, add cumin seeds and fennel seeds. When they sizzle, add chopped onion and cook for 2 minutes. Place okra one at a time on top of the onions and cook for a few minutes on each side. Turn over and cook. Cover and cook on medium low heat until tender.
Remove the okra that are done from the pan and continue to cook the rest. Taste and squeeze a little fresh lemon juice all over if it needs it, especially if you have not used the amchur or anardhana powders. Serve with rice or roti/chappathi.