In a blender or food processor, put garlic cloves, ginger, cilantro sprigs, green chilies and ½ cup water and process until completely smooth. Set aside.
Add the soaked and drained urad/maash dal to an Instant Pot/electric pressure cooker or stovetop pressure cooker. Add 3 cups of water and bring to a boil (I use 'high' saute mode). Wait for the scum to rise, then skim it off.
Add the blended mixture you prepared earlier. Also add ghee, salt, and turmeric powder. Mix well, lock the lid.
If using Instant Pot, select Manual (high pressure) and set the cook time to 35 minutes. If using stovetop pressure cooker, heat over medium-high (or medium if your burner is strong) until full pressure is reached. Reduce the heat just enough to maintain pressure, then begin timing 35 minutes.
After cooking, turn off the heat/device, let the pressure release naturally. Stir the dal for a couple of minutes. If you prefer a smoother consistency, use an immersion/hand blender (see tips in Note C below).
Set the Instant Pot to (less/low) saute mode. Mix in yogurt, 1 cup water and 1 teaspoon sugar. Then, gradually add in more water, if you like, until the dal reaches your desired consistency. Stir every few minutes so the daal doesn’t stick to the base of the pot. Meanwhile, get the tarka ready.
For tarka, heat ghee in a small pan/pot over medium-low heat. Once hot, add cumin seeds, chopped garlic, chopped green chilies, and let them sizzle for 10 to 15 seconds. Don't let the garlic burn.
Pour this tempered mixture over dal and stir to combine. Depending on the amount of extra water you've added, you may need to add a bit more salt. Taste the dal, and adjust if needed.
Finally, mix in cilantro and lemon juice. Turn off heat/device. Cover and let the dal rest for 10 minutes so the flavors get better infused. Serve with steamed basmati rice, roti, or naan.
Notes
Note A: Urad Dal – May be labeled under a different name. White lentils, split washed urad dal, dhuli urad dal, skinless split black lentil, maa(h) dal, white urid dal, maash dal, huskless-split black mapte beans. What you are looking for is a small white (or creamy-white) split lentil that doesn't have any black skin. Dal that is very old will not cook to a soft, creamy texture, even after pressure cooking.Note B: Chillies – I use Thai green chilies, but you can swap in other kinds and adjust quantity to suit your preference.Note C: Tip – The consistency of dal after pressure cooking should be mashable. If you want it to be smooth, use a potato masher, an immersion blender, or a countertop blender. When using the latter, let the dal cool, unless confident that your blender can handle hot food.