Set a large soup pot or Dutch oven on the stove over medium heat.

Add the olive oil to the pot and heat it until it looks loose and shiny, about 30 seconds.

Add the chopped onion and 1/2 teaspoon of the kosher salt to the pot. Cook, stirring every minute, until the onion softens and starts to look translucent, about 5 minutes.

Add the sliced garlic and grated ginger to the pot. Cook, stirring often, until both smell fragrant and no longer smell raw, about 1 minute.

Add the curry powder to the pot. Stir it through the onion mixture for 30 seconds so it toasts lightly in the oil.

Add the sweet potato cubes to the pot. Stir until the cubes are coated with the spiced onion mixture, about 1 minute.

Add the rinsed red lentils to the pot. Stir once so they are evenly mixed in with the vegetables.

Add the drained chickpeas, vegetable broth, and coconut milk to the pot. Stir well and scrape the bottom of the pot with a wooden spoon so nothing is stuck there.

Turn the heat to high and bring the stew to a boil.

When the liquid reaches a boil, turn the heat down to medium-low so the stew bubbles gently. Cook uncovered for 10 minutes.

Stir the pot well. Keep simmering until the sweet potato is tender when pierced with a spoon and the red lentils have started to break down, 12 to 15 minutes more.

Use the back of the spoon to crush a few sweet potato cubes against the side of the pot. Stir them back into the stew to thicken it slightly.