Start the soup: Set a large soup pot or Dutch oven on the stove over medium heat. Add the olive oil and heat it for about 1 minute, until it looks loose and shiny.

Add the chopped onion, diced carrots, and diced celery to the pot. Cook, stirring every minute or so, until the vegetables soften and the onion looks translucent, 6 to 8 minutes.

Add the sliced garlic and chopped rosemary to the pot. Stir for 1 minute, just until the garlic smells fragrant and does not brown.

Add the rinsed lentils to the pot. Stir them with the vegetables for about 30 seconds so they get coated in the oil.

Pour the vegetable broth into the pot. Add the kosher salt and black pepper, and stir well.

Turn the heat to high and bring the broth to a boil. This should take about 3 to 5 minutes.

When the pot reaches a boil, lower the heat so the soup stays at a gentle simmer. Leave the pot partly covered and cook for 20 minutes.

Stir the soup and check the lentils. They should be starting to soften but still have a little firmness in the center.

Add the drained chickpeas to the pot. Stir them into the soup and keep the pot at a gentle simmer.

Cook the soup for 10 to 12 minutes more, until the lentils are tender all the way through and the broth looks a little fuller from the lentils releasing starch.

Add the chopped escarole to the pot a handful at a time. Stir after each handful so the greens wilt and make room for the rest.

Simmer the soup for 3 to 5 minutes, until the escarole is tender but still bright green. Turn off the heat.