Set a large heavy pot or Dutch oven over medium heat and add the olive oil.

Start the base: Add the chopped onion, carrots, and celery to the pot.

Cook the vegetables for 8 to 10 minutes, stirring every few minutes, until they look soft and the onion is lightly golden at the edges.

Build the flavor: Add the sliced garlic to the pot.

Cook for 1 minute, stirring often, until the garlic smells fragrant and no longer looks raw.

Wake up the seasonings: Stir the tomato paste and dried rosemary into the vegetables.

Cook for 1 to 2 minutes, stirring, until the tomato paste darkens slightly and coats the vegetables.

Simmer the lentils: Add the rinsed lentils, vegetable broth, 1 1/2 teaspoons salt, and 1/2 teaspoon black pepper to the pot.

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

Lower the heat to maintain a gentle simmer and partially cover the pot.

Cook for 20 to 25 minutes, stirring once or twice, until the lentils are almost tender but still hold their shape.

Add the hearty ingredients: Add the drained chickpeas to the pot.