01 - Cook the pasta in a large pot of salted boiling water according to package instructions until al dente. Drain and reserve 1/2 cup of pasta cooking water.
02 - While the pasta is cooking, heat olive oil and butter in a large skillet over medium heat. Add the onion and sauté for 2-3 minutes until soft.
03 - Add the minced garlic and cook for 1 minute until fragrant.
04 - Add the fresh spinach and cook, stirring, until wilted, about 2-3 minutes.
05 - Pour in the heavy cream, bring to a gentle simmer, and stir in the grated Parmesan and nutmeg. Simmer for 2-3 minutes until the sauce thickens slightly.
06 - Add the drained pasta to the skillet and toss to combine, adding reserved pasta water as needed to loosen the sauce.
07 - Season with salt and freshly ground black pepper to taste.
08 - Serve immediately, garnished with extra Parmesan and a sprinkle of black pepper.