Start the pot: Set a large heavy pot or Dutch oven on the stove over medium heat. Add the olive oil and let it warm for about 30 seconds.

Soften the onion: Add the chopped onion and 1/2 teaspoon of the kosher salt to the pot. Cook, stirring often, for 5 to 6 minutes, until the onion looks soft and glossy.

Add the garlic and cumin: Add the chopped garlic and ground cumin to the pot. Stir for 30 seconds, just until the garlic smells fragrant.

Cook the chile paste: Add the aji amarillo paste to the pot. Stir it into the onion mixture and cook for 1 minute so the paste darkens slightly and coats the bottom of the pot.

Add the potatoes: Put the potato pieces into the pot. Stir for 1 minute so they pick up the onion and chile mixture.

Build the stew: Add the lentils, the drained chickpeas, the vegetable broth, and 2 cups of water to the pot. Stir in the remaining 1 teaspoon kosher salt.

Bring it up to a boil: Turn the heat to high and bring the pot to a full boil. Stir once so the lentils do not settle on the bottom.

Simmer until the lentils start to soften: Lower the heat to medium-low so the liquid bubbles gently. Cover the pot partway with a lid and simmer for 20 minutes.

Finish cooking the lentils and potatoes: Uncover the pot and stir. Keep simmering for 10 to 15 minutes more, until the lentils are tender and the potatoes are easy to pierce with a fork.

Thicken the broth: Use the back of a wooden spoon or a potato masher to crush a few potato pieces and some chickpeas against the side of the pot. Stir them back into the broth to make the stew a little thicker.

Add the fresh finish: Stir half of the chopped cilantro into the pot. Add the juice from 1 lime and stir again.

Taste and adjust: Taste the stew. Add more salt if it needs it, or a splash of water if you want a looser, more brothy texture.