Serves 6-8

2 tablespoons olive oil
1/2 large onion, chopped small
2 cloves of garlic, sliced
1/2 cup brown lentils, picked through to remove any abnormal ones
1 cup tomato purée (I like Pomi brand)
3 cups vegetable broth
1 bay leaf
1 teaspoon Herbes de Provence
2 tablespoons unsalted butter (optional)
1/2 teaspoon Kosher salt or to taste, a pinch of sugar, and freshly ground black pepper
1 pound spelt or whole-grain spaghetti
5 ounces fresh spinach leaves, washed well
Grated Parmesan cheese, for serving

1. In a large saucepan, heat the olive oil over medium heat. Sauté the onions and garlic, stirring frequently with a wooden spoon, until fragrant and soft, about 5 minutes.

2. Add the lentils and stir to coat. Add the tomato purée, stock, bay leaf and Herbes de Provence. Bring to a boil, then lower the heat and simmer covered, stirring occasionally to prevent burning, until the lentils are soft, about 45 minutes. Do not add the salt until the lentils have finished cooking or they will remain hard. At the end of the cooking process, season the sauce with salt, sugar, and pepper.

3. While the sauce is cooking, bring a large pot water to a boil. Add a handful of salt. Stir in the pasta.

4. Once the pasta is about a minute from being al dente (tender but not mushy), drop in the spinach leaves and cook them along with the pasta. Drain the pasta and spinach, reserving 1/2 cup of the cooking water to add to the pot of sauce.

5. In a large serving bowl, toss the pasta and spinach with the sauce. Serve with the Parmesan cheese on the side.