1. Place lentils in a large bowl and add warm tap water to cover by 1 inch.  Let soak.
2. Halve the leeks lengthwise; run under warm water to release any grit.  Thinly slice leeks crosswise.
3. Heat the oil in a Dutch oven or large pot over medium-high heat.  Add leeks and cook, stirring occasionally, until golden brown and crispy, 5 to 10 minutes.  Transfer half the leeks to a bowl to use for garnish and sprinkle with 1/4 teaspoon salt.
4. Stir the garlic into the pot with remaining leeks and cook for 15 seconds until fragrant.  Stir in rice and saute for 2 minutes.  Stir in cumin, allspice and cayenne, saute for 30 seconds or so.
5. Drain the lentils and stir into the pot.  Add 4 1/4 cups water, 2 teaspoons salt, the bay leaf and the cinnamon stick.  Bring to a simmer.  Cover and cook over low heat for 15 minutes.  Rinse the greens in a colander and spread damp leaves over the lentil mixture.  Cover and cook for 5 minutes more, until the rice and lentils are tender and greens are wilted.  Remove from heat and let stand, covered, for 5 minutes.  Serve sprinkled with reserved crispy leeks.

Recipe from Melissa Clark at The New York Times.