I call this "pantry pasta" because it can be made with whatever ingredients you have on hand in your fridge and pantry! An easy to customize recipe base that can be ready on the table in about 15 minutes.
Bring a large pot of salted water to a boil. Add spaghetti, return to a boil, and cook, stirring occasionally, until al dente, about 8 minutes. Reserve 1/2 cup pasta water, and drain pasta. Toss pasta in 1 tablespoon butter and set aside.
During the last few minutes of pasta cook time, add oil to a large saucepan and heat over medium-high. Add garlic and cook until fragrant, about 1 minute. Add anchovies and red pepper flake and cook, stirring often, for 1 minute.
Carefully transfer cooked pasta to saucepan of garlic mixture. Add 1/4 cup pasta water, remaining 1 tablespoon butter and Parmesan cheese and cook, using tongs to toss constantly, until liquid reduces and coats pasta, 1 to 2 minutes.
2 tablespoons unsalted butter, 1/4 cup Parmesan cheese
Add lemon juice and zest, and toss to combine (and add more reserved pasta water as needed). Salt and pepper to taste.
Zest of 1 lemon, Juice of 1 lemon, salt and pepper
Serve immediately, top with more cheese and/or herbs, and enjoy!
1 tablespoon chives, 1 tablespoon green onions for topping, 1 tablespoon parsley