First, prep the okra. Wipe each pod with a damp cloth and spread them on a towel to air-dry completely. This is key to preventing a slimy texture. Trim off the tops and tails, then slice the pods crosswise into ½-inch / 1. 25 cm pieces.
Place a large frying pan or sauté pan over medium-high heat and add the oil.
Once the oil is hot, add the urad dal.
Fry for about 30-45 seconds until it just begins to turn a light golden color.
Immediately add the mustard seeds and cumin seeds. As soon as the mustard seeds start to pop (this will only take a few seconds), add the slit green chili (or chili powder), crushed curry leaves, and the chopped onion. Be careful, as the curry leaves will splutter.
Sauté the onions, stirring frequently, for about 6 minutes, or until they soften and just start to brown at the edges.
Stir in the ground turmeric, cook for 10 seconds, then add the chopped okra to the pan.
Lower the heat to medium-low and gently stir-fry for 5-6 minutes, allowing the okra to cook without a lid.
Add the salt and lemon juice, and stir gently to combine.
Sprinkle 1-2 tablespoons (30 ml / 1 fl oz) of water over the okra to create a little steam.
Lower the heat to low, cover the pan, and cook for another 5-6 minutes, or until the okra is tender but still has a slight bite.
Check once during cooking, adding another splash of water only if it seems to be sticking.
Taste and adjust salt if needed before serving.
Don't cover the pan for the initial stir-frying period.
Cooking the okra uncovered allows moisture to escape, further preventing any sliminess.
