In a large Dutch oven or stock pot, heat oil over medium-high heat until shimmering. Add garlic and cook until garlic begins to turn golden, but not scorched, about 1-2 minutes.
Stir in capers, anchovy fillets, olives, tomatoes, and crushed red pepper (I like 1 teaspoon). Heat to boiling, reduce heat, and simmer uncovered until slightly thickened, about 30-40 minutes.
Meanwhile, bring 4 quarts water and 1 tablespoon salt to boil. Add spaghetti and cook until al dente, about 9 to 10 minutes. Drain well and add to sauce mixture, tossing pasta until evenly coated.
Notes
Capers:Capers are the little pickled blossoms of a French shrub. I highly recommend giving the briny beauties a shot, especially in this salty and savory puttanesca sauce! I suggest 4 tablespoons capers for the 6-serving sauce. Scale up or down as you see fit.
Anchovy filets: While anchovies are easy to find in the tinned fish section these days, I seek out olive oil-packed anchovies in a little jar for easy storage. You can also opt for a generous squirt of anchovy paste instead; this is sold in toothpaste-like tubes at specialty grocery stores or online. One 1/4 teaspoon anchovy paste is equal to one anchovy filet.
Spaghetti: This recipe calls for spaghetti, but it's certainly not the end-all, be-all of pastas for puttanesca. Other long, thin noodles like linguine or bucatini also works beautifully.
Yield: This recipe makes six generous servings of a little more than 3 ounces of pasta. I find this rich enough that this Spaghetti alla Puttanesca portion satisfies as a main dish, but multiply as desired.
Storage: Store leftovers covered in the refrigerator for up to 4 days.