Step 1

Heat the oil in a heavy pan and sauté the onion and celery until softened but not colored. Add the garlic and spices and cook for 1 minute. Then add the ras el hanout, lentils, tomatoes, and stock or water. Bring to a boil, reduce to a simmer, and cook for 30 to 45 minutes, or until the lentils start to break down and sort of become a purée. The mixture will be quite thick and more dal-like than soup-y. If you prefer a thinner consistency, add more stock or water as necessary.

Step 2

Slick a skillet with the olive oil, place it over medium-high heat, and toss in the sliced onions. Heat until the onions are golden brown and crisp at the edges. Add the cinnamon, sugar, and chile and stir just until the onions are coated. Then let the onions cook only until the sugar has dissolved. Immediately add the lemon juice—and be ready to dodge some spatters. Remove from the heat and season with salt and pepper.

Step 3

Season the lentil soup with salt and pepper and stir in the chopped cilantro. Ladle the soup into bowls and add a dollop of yogurt and the chile-fried onions. Garnish with cilantro.