01 -
Fill a large pot with generously salted water and bring to a rolling boil. Add the spaghetti and cook according to package instructions, approximately 9-10 minutes, until al dente. Reserve 240 ml of pasta cooking water, then drain the pasta without rinsing.
02 -
Set a large skillet over medium heat. Melt the butter, then add the garlic and red pepper flakes. Stir for about 1 minute until the garlic becomes fragrant.
03 -
Pour in the lemon juice and half of the reserved pasta water into the skillet. Once bubbling, add the baby spinach leaves and cooked spaghetti. Toss to coat the pasta and wilt the spinach until just softened.
04 -
Remove skillet from the heat. Add grated parmesan, lemon zest, freshly ground black pepper, and a pinch of salt. Toss to thoroughly combine. Adjust the sauce consistency with more reserved pasta water, up to 60 ml, if needed. Serve immediately.