2 tablespoons olive oil
1 onion, diced
3 garlic cloves, minced
3 carrots, peeled and diced
3 celery stalks, diced
3 small potatoes, diced
1 ½ cups green or brown lentils, rinsed
One 28-ounce can diced tomatoes, undrained
3 cups vegetable broth
1 teaspoon kosher salt
1 teaspoon freshly ground black pepper
1 tablespoon garam masala
1 teaspoon ground cumin
2 cups chopped spinach
1 tablespoon freshly squeezed lemon juice
Heat the oil in a stockpot or Dutch oven over medium-high heat. Add the onions and cook, stirring frequently, until softened, about 5 minutes. Add the garlic and cook, stirring, 30 seconds more.
Stir in the carrots, celery, potatoes, lentils, tomatoes, broth, salt, pepper, garam masala and cumin. Raise the heat to high, and bring to a boil. Reduce the heat to medium-low and let simmer, uncovered, until the potatoes are tender, about 15 minutes.
Stir the spinach into the stew, and let simmer another minute or two, until the spinach is wilted. Stir in the lemon juice. Serve hot.