When you are starving and can't wait for take-out, lean on this pasta dish as your new go-to. Using the most basic ingredients you probably have in your pantry right now, pasta will never be the same once you taste this. By focusing on salt, fat, acid and heat, you're going to revel in the simplicity and flavorful triumph of this dish.
Fill a large pot with water and add the salt. Set over high heat and bring to a rolling boil.
Add spaghetti and cook until almost al dente. Reserve one cup of cooking water and set aside. Drain pasta.
Set a large pan over low heat and swirl in the olive oil, garlic and red chile flakes. Gently heat oil until garlic is aromatic, about 1 minute. Be careful not to burn the garlic.
When the pasta is ready, increase the heat to high and add drained pasta, butter, and half of the reserved cup of water.
Quickly toss pasta without stopping until the sauce emulsifies, thickens and coats the noodles, 1-2 minutes. If necessary, add splashes of remaining cooking water to stretch the sauce until it looks creamy and completely coats the noodles.
Turn off the heat and toss in parsley, half the lemon zest and all of the juice. Season with plenty of salt and black pepper to taste. Serve with remaining lemon zest scattered over the top.