Put garlic, onion, herb, and anchovy in a blender. Add oil half way up solids, blend until smooth.
Scrape paste out into sauce pan and cook over medium heat, stirring all the while.
As water evaporates, the oil will start to separate out and the onion and garlic will begin to fry. Keep going until the kitchen fills with the smell of the aromatics. Toast as much as you like but don’t burn it.
Pour canned tomatoes in mixer container to rinse out the leftover paste, then pour tomatoes into the pan.
Turn down, stir to scrape up any bits, and stir in olives, capers, and chili flakes.
Bring it up to a simmer, checking along the way for salt, pepper and chili. Turn off heat once it has simmered for 2-3 minutes.
When you are ready to eat, cook your pasta in a pot with lots of boiling salted water until al dente. Drain and transfer to a large mixing bowl and add sauce. Toss to coat.
You can grate a little cheese in here too. If the pasta is too dry, add some of the pasta water to loosen things up.
Transfer to serving bowl or plate individually, artfully twisting pasta and topping with remaining sauce and garnish with cheese and herb leaves.