In a large pot, heat 2 tablespoons of olive oil over medium heat. Once shimmering, add 1 diced onion, 2 minced garlic cloves, 2 chopped carrots, and 2 chopped celery stalks. Sauté the mixture for about 5 minutes, stirring occasionally, until the vegetables soften and the onion becomes translucent, filling your kitchen with a fragrant aroma.

Add one 14-ounce can of diced tomatoes (with juices), 1 cup of dried brown lentils, and 4 cups of vegetable broth to the pot. Sprinkle in 1 teaspoon of ground cumin, ½ teaspoon of ground coriander, and kosher salt to taste. Stir everything together until well combined, ensuring the lentils are submerged in the broth to absorb all the flavors in your lentil soup.

Bring the mixture to a boil over high heat, then reduce the heat to maintain a gentle simmer. Leave the pot uncovered and cook for approximately 25 minutes. Stir occasionally and watch for the lentils to become tender and the soup to thicken, creating a hearty texture that invites you to dig in.

Once the lentils are tender, stir in 2 cups of baby spinach and the juice of 1 lemon. Cook for an additional 30 seconds over low heat, just until the spinach begins to wilt and adds a vibrant pop of color to your Hearty Vegan Lentil Soup.

Remove the pot from heat, and ladle the warm soup into bowls. Enjoy your nourishing lentil soup immediately while it's hot, perhaps garnished with fresh herbs if you desire. Prepare to enjoy a comforting bowl that envelops you in warmth and flavor!