Spaghetti With Lentils, Tomato and Fennel

Preparation

1. Step 1

   Rinse lentils. Put them in a saucepan and cover with water by 1 inch. Toss in Parmesan rind, if using. Add a good pinch of salt and place over high heat. Bring to a boil, then reduce heat to a simmer and cook until soft, about 30 minutes. Drain lentils and reserve cooking water.

2. Step 2

   As lentils cook, put 3 tablespoons oil in a skillet over medium-high heat. When oil is wavy, add diced onion and fennel, and season with salt and pepper. Add fennel seeds and red-pepper flakes. Cook, stirring, until softened and slightly caramelized, about 10 minutes.

3. Step 3

   Add garlic, passata and 2 or 3 tablespoons finely chopped fennel fronds. Stir to combine and add drained lentils. Turn heat to medium and simmer for 10 minutes or so, until somewhat thickened. Taste and correct seasoning, then cook for 5 minutes more, so the flavors meld. Add lentil cooking water as necessary to keep everything saucy.

4. Step 4

   As sauce cooks, set a large pot of salted water to boil. Cook the spaghetti until al dente. Divide among individual bowls and ladle sauce over each serving. Top with shavings of ricotta salata and more chopped fennel fronds. Drizzle with a little extra-virgin olive oil, if desired.