Prep your vegetables: Dice the onion into small pieces (about 1/2-inch), cut carrots and celery into small 1/2-inch chunks, and mince garlic. Rinse the red lentils in a fine mesh strainer under cold water for 1–2 minutes until water runs clear. This takes about 5 minutes total. Checkpoint: You have all your ingredients prepped and ready to go.

Heat the pot: Pour 2 tablespoons olive oil into a large pot (at least 5-quart capacity) and set heat to medium. Wait 1–2 minutes until oil shimmers (moves easily when you tilt the pan). Checkpoint: Oil is hot and ready for vegetables.

Sauté the aromatics: Add diced onion, carrots, and celery to the hot oil. Stir occasionally with a wooden spoon for 5–7 minutes until vegetables are soft and onion turns translucent (see-through). The kitchen should smell sweet and savory. Checkpoint: Vegetables are soft and smell fragrant.

Add garlic: Add minced garlic to the pot and stir constantly for exactly 30–60 seconds. You will smell a strong, pungent garlic aroma—this means the garlic is ready. Do not let it brown or it will taste bitter. Checkpoint: Garlic is fragrant but not brown.

Bloom the spices: Add 1 teaspoon ground cumin, 1 teaspoon paprika, 1/2 teaspoon turmeric, and 1/4 teaspoon cayenne pepper. Stir constantly for 20–30 seconds until the spices coat the vegetables and smell warm and toasty. Checkpoint: Spices are evenly distributed and smell aromatic.

Add the lentils and liquid: Pour in 1 cup rinsed red lentils, 4 cups vegetable broth, and 1 can (14 ounces) diced tomatoes with all their liquid. Drop in 1 bay leaf. Stir everything together for 1 minute. Checkpoint: All ingredients are combined and the liquid covers everything by about 1 inch.

Bring to a boil: Increase heat to high and let the soup come to a full boil—you will see large bubbles breaking the surface actively for 1–2 minutes. Checkpoint: Soup is at a rolling boil.

Simmer the soup: Reduce heat to low (about medium-low, roughly 3 on a scale of 1–10). Place the lid partially on the pot (leave it slightly ajar so steam can escape). Simmer for 15–20 minutes, stirring occasionally, until the lentils are completely soft and starting to fall apart when you stir. They should look like they're breaking into the broth. Checkpoint: Lentils are completely tender and the soup is creamy-looking.

Remove the bay leaf: Use a spoon to carefully fish out the bay leaf and discard it. Checkpoint: Bay leaf is removed.

Adjust consistency (optional blending): If you like a completely smooth soup: Use an immersion blender and blend for 2–3 minutes, moving it around the pot, until no chunks remain and the soup is creamy. If you like it chunky: Leave it as is. If you want it partially blended: Blend for 30–45 seconds for a semi-smooth texture with some lentil pieces remaining. Checkpoint: Soup has reached your desired texture.

Add lemon juice and season: Stir in 2 tablespoons fresh lemon juice. Taste the soup with a spoon. Add salt and black pepper a pinch at a time, tasting after each addition, until it tastes balanced and not bland. You should taste the lentils, the warm spices, and a slight tang from the lemon. Checkpoint: Soup is well-seasoned and tastes delicious.

Serve immediately: Ladle soup into bowls using a ladle (soup will be hot—about 180–190°F). Top each bowl with a small handful (about 1 tablespoon) of fresh chopped cilantro and 1 tablespoon of Greek yogurt or sour cream. Serve right away while steam is still rising. Checkpoint: Soup is plated and ready to eat.

Troubleshooting: If soup is too thick: Add 1/2 cup more broth at a time and stir until you reach desired consistency.

If soup is too thin: Simmer uncovered for 5 more minutes, or blend a portion to thicken naturally.

If lentils are still hard after 20 minutes: The heat may be too low or your lentils are old. Increase heat slightly and continue cooking for 5–10 more minutes.

If soup tastes bland: Add more lemon juice (start with 1 tablespoon more) or more salt, tasting after each addition.

If soup tastes too spicy: Stir in a splash of broth or a dollop of Greek yogurt to cool it down.