Start your spaghetti boiling in a big pot of salted water. Add a glug of white vinegar to keep the pasta sticking, if you'd like.

Meanwhile, heat the 3 tablespoons olive oil in a very large skillet over medium heat. Add the garlic and the red pepper flakes and cook until the garlic is softened. Add the tuna and the olive oil it’s packed in – do not drain it! Stir it around for a minute or two.

Drain your pasta, reserving 1/2 cup of the water the pasta cooked in. Add the drained pasta to the skillet, and stir everything around really well. Add the reserved pasta water and stir until the noodles all seem to be coated with the olive oil. Add the parsley and salt and pepper to taste.