Add spaghetti to pot of salted boiling water and follow package directions to cook al dente.

With about 5 minutes remaining for the pasta, add olive oil, garlic clove, and parsley stems to a saucier.

Sauté the garlic over medium heat until it begins to turn golden and begins to release its aroma, no more than 2 minutes.

Remove garlic from the oil. Add the anchovies and red pepper flakes to the oil and stir until the anchovies dissolve, 1-2 minutes.

Add olives and capers to the pan and toss.

Add tomatoes to the pan and combine. Allow contents to simmer until tomatoes are soft, 2-3 minutes.

Add most of the parsley to the sauce, reserving 2 sprinkles to garnish for serving.

Transfer spaghetti to the sauce with a ladle of pasta water and finish, stirring and tossing until sauce is emulsified and clings to the pasta.

Plate the spaghetti, pour any additional sauce remaining over the top, and garnish with remaining fresh parsley.