Ingredients

• 1 1/2 teaspoons kosher salt, plus more for pasta water and seasoning
• 8 ounces (225 grams) spaghetti
• 1 cup (235 ml) pasta cooking water, reserved
• 1 1/4 pounds (570 grams) zucchini, trimmed and coarsely grated
• 6 tablespoons (85 grams) unsalted butter
• 4 garlic cloves, minced
• 1/4 teaspoon red pepper flakes, or more to taste
• 1/2 cup (45 grams) grated parmesan
• A handful of fresh basil leaves, thinly sliced

Instructions

1. Bring a large pot of well-salted water to a boil. Cook the spaghetti until just shy of al dente, about one minute less than the package suggests. Before draining, scoop out 1 cup of the pasta water and set it aside.
2. In a wide pan over medium-high heat, melt the butter. Add the garlic and stir for about one minute, just until fragrant.
3. Add the grated zucchini, kosher salt, and red pepper flakes. Cook for 13 to 15 minutes, stirring occasionally. The zucchini will release liquid, which will eventually evaporate, leaving it soft and concentrated. If it begins to brown, lower the heat slightly.
4. Continue cooking for another 2 minutes, stirring often and pressing the zucchini with the edge of a spoon or spatula to break it down until it becomes nearly spreadable.
5. Pour in 1/2 cup of the reserved pasta water, scraping up any bits from the pan. Add the drained spaghetti and cook everything together for about 2 minutes.
6. Using tongs or two forks, toss the pasta thoroughly so the zucchini butter coats the strands. Add more pasta water as needed to loosen the sauce.
7. Stir in half of the parmesan and half of the basil. Transfer to a serving bowl and finish with the remaining parmesan and basil before serving.