Rinse toor dal well under running water until the water runs clear, then soak it in sufficient water for about 30 minutes.
Transfer the drained dal to a pressure cooker. Add 1 & 1/2 cups of water, 1/2 teaspoon salt, 1 teaspoon oil, and 1/4 teaspoon turmeric. (Adding oil prevents frothing and spilling from the pressure cooker). Mix well.
Pressure cook the dal for 3 whistles on high heat. Then lower the heat and simmer for another 5 minutes. Switch off the heat and set the cooker aside.
Once the cooker depressurizes, open the lid and mash the dal with a wired whisk or spoon for a smooth consistency. You may leave it as it is if you prefer it that way.
Heat 2 tablespoons oil in a heavy-bottomed pot, add cumin seeds. Once it crackles, add a pinch of hing, minced garlic, minced ginger, slit green chillies, and dried red chillies.
Stir-fry, until fragrant.
Add finely chopped onions, sauté until it turns a light golden brown.
Add the remaining 1/4 teaspoon turmeric and red chilli powder or cayenne pepper, sauté for another 30 seconds.
Next, add finely chopped tomatoes along with 1/2 teaspoon salt and sauté until it turns mushy and you see oil oozing from the sides.
Add chopped spinach, and stir-fry until it wilts, about 1 to 2 minutes.
Now, add the cooked dal, and give everything a good mix.
Add about 1/2 to 3/4 cup of water or as per your desired consistency, bring to a boil. Check for seasonings and adjust accordingly. Simmer for another 5 minutes.
Drizzle some lemon juice and mix well.
Prepare the second tempering by heating ghee in a small pan, add cumin seeds, when it crackles, add 1 dred chili.
Fry for a few seconds until the chili changes color.
Switch off the heat, add Kashmiri chilli powder. Mix well and pour it over the dal immediately. Mix it well with the dal, and serve hot with rice or any other flatbread.