1. Bring a large pot of well-salted water to a boil and cook the spaghetti or linguine until just al dente according to package directions. Before draining, scoop out about 2 cups of the starchy pasta cooking water and set aside.

2. While the pasta cooks, place the pine nuts in a dry skillet over medium-low heat. Toast, stirring frequently, until fragrant and lightly golden, 3–4 minutes. Transfer to a small bowl so they do not continue to brown.

3. In the same skillet, add the olive oil over medium heat. Stir in the minced garlic and cook just until fragrant and barely golden, 30–60 seconds. Turn the heat to low to keep the garlic soft and prevent burning.

4. In a large mixing bowl, whisk together the ricotta, 3/4 cup of the Parmesan, the lemon zest, and 2 tablespoons of lemon juice. Season with the sea salt, black pepper, and red pepper flakes if using. Whisk in about 1/2 cup of the hot pasta water until the mixture becomes smooth and creamy.

5. Add the drained hot pasta to the skillet with the garlic. Pile the baby spinach on top of the pasta and toss gently over low heat so the spinach begins to wilt.

6. Pour the lemon ricotta mixture over the pasta and toss, adding more reserved pasta water a little at a time until every strand is coated in a silky sauce. The sauce should look glossy and cling nicely to the noodles.

7. Taste and adjust seasoning with more salt, pepper, or lemon juice as desired. When the spinach is fully wilted and the sauce is hot and creamy, divide the pasta among 4 bowls.

8. Top each serving with the remaining Parmesan cheese and a generous sprinkle of toasted pine nuts. Serve immediately, with extra lemon wedges and red pepper flakes on the side if you like.