Add the olive oil and thinly sliced shallots to a large stainless steel frying pan on medium/low heat. Season generously with salt and pepper and sweat for around 10 minutes.

Add the garlic, anchovies, red pepper flakes, chili flakes, parsley stems, and tomato puree into the pan. Continue to fry over medium/low heat for another 8 minutes, stirring frequently.

During this time, add the spaghetti to heavily salted pasta water. Set your timer to 2 minutes minus the packet time.

Once the puree has darkened and the onions are looking really caramelized, transfer the undercooked pasta into the pan along with 2 ladles of pasta water. Stir to combine.

Serve the caramelized shallot pasta with finely chopped garlic and fresh parsley.