Bring a 6-quart / 5.7 L pot of water to a rolling boil and salt it generously. Add the spaghetti and cook 1 minute less than the package says, until just shy of al dente.

While the pasta cooks, heat 1 tbsp olive oil in a 10-inch / 26 cm skillet over medium heat. Add the breadcrumbs and toast 3 to 4 minutes, stirring often, until golden and crisp. Transfer to a bowl and season with a pinch of salt.

Wipe out the skillet. Add the remaining 5 tbsp olive oil, the sliced garlic and the chili flakes over low heat. Cook 2 to 3 minutes, stirring often, until the garlic turns pale gold. Pull the pan off the heat immediately if it starts to brown.

Just before draining, scoop out 1 cup / 240 ml of the pasta water and set it aside. Drain the pasta.

Add the drained pasta straight into the skillet with the garlic oil. Toss over low heat, adding splashes of the reserved pasta water, for 1 to 2 minutes until the pasta finishes cooking and the sauce turns glossy and clings to the strands.

Remove the skillet from the heat. Sprinkle in the pecorino a little at a time, tossing until it melts smooth. Add more pasta water if the sauce looks tight.

Stir in the chopped parsley and a good crack of black pepper.

Divide among bowls, top with the toasted breadcrumbs and extra pecorino, and serve right away.