Cook the Lentils: In a large, heavy-based saucepan, combine the rinsed lentils, water, and ground turmeric. Bring to a boil over high heat—you’ll see a frothy scum rise to the surface, which you can skim off with a spoon. Reduce the heat to a gentle simmer, partially cover, and cook for 25–30 minutes. The lentils will swell, soften, and begin to break apart, and the liquid will turn a deep, sunny yellow. The dal is ready when the lentils are completely tender and mash easily against the side of the pan with a spoon. Stir in the salt.

Prepare the Tempering (Tadka): While the lentils simmer, set a small frying pan or skillet over medium heat. Add the ghee and let it melt until it shimmers and releases a nutty aroma. Drop in the cumin seeds and black mustard seeds. Watch carefully—within 30 seconds, the mustard seeds will start to pop and pop, a sound like tiny firecrackers, and the cumin seeds will turn a few shades darker. This is the moment the kitchen fills with an intoxicating fragrance.

Sweat the Aromatics: Immediately add the finely diced onion to the pan with the sputtering seeds. Stir well, coating the onion in the spiced ghee. Cook for 6–8 minutes, stirring occasionally, until the onion turns translucent and begins to take on a pale golden colour at the edges. The sizzling sound will soften as the onion releases its moisture. Add the minced garlic, grated ginger, and slit green chillies. Cook for another minute, until the garlic is fragrant and the raw smell has faded.

Build the Sauce: Tip in the finely chopped tomatoes, ground coriander, and a pinch of salt. Stir everything together. The tomatoes will immediately begin to release their juices, and the mixture will become saucy and thick. Cook for 5–7 minutes, stirring occasionally, until the tomatoes have completely broken down and the oil begins to separate and glisten on the surface of the masala. You’ll notice a rich, deep red colour developing.

Combine and Simmer: Pour the entire tempering mixture into the pot of cooked lentils. Stir well to combine. Add the garam masala and bring the dal back to a gentle simmer. Let it bubble away for 5 minutes, allowing the flavours to meld. The dal will thicken slightly, and the colour will deepen to a warm, golden-orange. Taste and adjust the salt and lemon juice to your liking.

Finish and Plate: Remove the dal from the heat. Stir through the chopped fresh coriander and a squeeze of lemon juice. For a truly impressive presentation, ladle the dal into a wide, shallow bowl. Create a slight well in the centre with the back of your spoon. If you have extra ghee, heat a small knob in a pan, add a pinch of cumin seeds and a dried red chilli, and when they sizzle, pour the hot oil into the well of the dal. It will hiss and pop, creating a dramatic, aromatic focal point. Finish with a swirl of yoghurt or a spoonful of fresh coriander chutney.