How do I get spaghetti soft and chewy, not mushy?
Cook it until it is just shy of al dente (still a little toothy), then finish it in the sauce for 1 to 2 minutes. That finishing step softens the noodle while keeping the chew. Mush happens when you fully cook the pasta in water and then keep cooking it in sauce.
Do I really need to save pasta water?
Yes. Pasta water is the secret ingredient that makes the sauce cling. It is salty and starchy, and the starch helps emulsify the fats (butter and oil) with the water so you get a smooth, glossy coating instead of a broken, greasy situation. It also lets you loosen the sauce without watering it down.
Can I make this without cream?
Absolutely. Swap the cream for 1/2 cup pasta water and add an extra tablespoon of butter at the end. It will be glossy and rich, just less plush.
My sauce turned grainy after adding Parmesan. What happened?
Usually the heat was too high or the cheese was not finely grated. Take the skillet off the heat for 30 seconds, add a splash of warm pasta water, and toss. Next time, let the sauce cool slightly before adding cheese, and use finely grated Parmesan (Parmigiano-Reggiano melts especially well).
Sliced or minced garlic?
Sliced gives you sweet little garlic chips throughout. Minced melts into the sauce for a more even garlic flavor. Either works. Just keep the heat at medium and stir constantly so it turns fragrant, not brown.
What protein works here?
Keep it easy: sautéed shrimp, crispy pancetta, rotisserie chicken, or white beans. Add cooked protein at the end so it warms through without overcooking.