12 oz spaghetti or other dry pasta
5 T olive oil, divided
4 cups chopped scallions
2 garlic cloves, finely chopped
1 t grated lemon zest
salt and pepper, to taste
1/2 c grated Parmesan cheese

1. Cook spaghetti until al dente or to your preference.

2. Meanwhile, heat 3 tablespoons olive oil in a large, heavy skillet over medium heat. Add scallions and garlic, and cook, stirring occasionally, until scallions are softened and garlic begins to turn golden, about 5 minutes. Watch that the garlic doesn’t start to burn–if it does, take the skillet off the heat.

3. Transfer scallion mixture to a blender or food processor. Add zest, salt, pepper, and remaining 2 T olive oil. Carefully remove 1/2 cup of the pasta-cooking water. Add to other ingredients. Purée until smooth.

4. Drain pasta in a colander and return to pot. Toss pasta with scallion purée and cheese. Taste for seasoning, adding more salt and pepper, if you like. Serve hot.