Wash lentils and soak for 2 hours. Drain the soaked lentils, and place in a pot with water (about 3 cups water).
Add salt, red chili powder, turmeric, coriander powder and garlic paste. Bring to a boil, and turn heat to low.
Cook the lentils on low heat till soft, which will take about an hour.
Once the lentils are almost tender, whisk well or stir & mash with a wooden spoon for 2 -3 minutes so that some of the lentil grains soften & break making the daal rich and creamy. You can also pulse 1 - 2 times with a hand blender. If necessary, add water and then cook for a couple of minutes till the required gravy consistency is reached.
Add lemon juice and mint leaves, and give it a stir.
When the lentils are almost ready heat oil for tempering (tarkin a small frying pan or wok.
Once the oil is hot, add sliced onion followed by the garlic 2 minutes later. Cook till golden brown. Make sure they don’t burn.
Pour the onion, garlic and the oil of the tempering (tarkover the hot lentils. Be careful as the oil will sizzle.
Serve hot with rice or roti.