Wash and rinse the lentils and soak for 6-8 hours at room temperature. (If not using a whole lentil you can get away with a shorter soak time).
Toss the water from the soaking lentils. Fill a large pot with fresh water and add the lentils making sure there is enough water to cover the lentils with about half an inch of water. Bring to a boil and simmer till the lentils are softened. About 25 minutes.
While the lentils cook, wash and rinse the basmati rice. Allow the rice to soak in water while the lentils finish cooking.
When the lentils are at your desired softness. Add the rice and enough water to reach the top of the rice (about 2-3 cups). Add salt to taste, a splash of oil, 2-3 black peppercorns and a bay leaf. Bring to a boil on medium-high. For more of a khichadi soup consistency, see recipe notes below.
Allow the rice to absorb all the water. When the water is no longer visible, cover and turn the heat down to low and allow the khichadi to steam for at least 15 minutes.
When the khicadhi is almost done steaming, in a separate small frying pan heat 1/4 cup oil with 1 tbsp minced garlic and 1 tsp cumin seeds. When the garlic starts to get fragrant add the dried red chilli.
Immediately remove the lid from the khichadi and pour the tardka onto the khichadi. Fluff gently with a fork and serve immediately.
Notes
For a Khichadi Soup: For a more soupy consistency, add more water when you add the rice. Bring to a boil and keep simmering until the rice starts to break down. You will need to add water to keep the consistency of the khichadi more like a thick soup. For a smoother consistency, use an immersion blender. Finish with the garlic cumin tardka and a big dollop of yogurt for serving. Bonus leftover makeover: For day two khichadi you can revive it by turning it into crispy garlicky khichadi. In a large frying pan heat a splash of oil, add 1 tsp minced garlic and 1 tsp cumin seeds. Spread out the rice into the pan and cover. Cook on medium low for 10-15 minutes until the edges of the rice starts to turn golden and crisp. Remove from pan by flipping into a plate and serve immediately.