Mound the flour and salt in a large bowl or on a work surface, make a well, and pour in the warm water and olive oil. Mix with a fork, then your hands, until a shaggy dough forms.

Knead 8 to 10 minutes until smooth and elastic, the dough should spring back when pressed. Cover with a bowl or plastic wrap and rest 30 minutes at room temperature.

Cut the dough into 4 pieces. Roll one piece at a time under your palms into a thick rope about 4-5 mm across, then cut into 25-30 cm strands. Dust with flour and set on a floured tray. Repeat with remaining dough.

Warm the olive oil in a 12-inch / 30 cm skillet over medium-low heat. Add the sliced garlic and chili flakes, cooking 2 to 3 minutes, stirring constantly, until pale gold and fragrant. Pull the pan off heat immediately if it starts to brown.

Pour in the tomato passata and add the salt, stirring to combine. Simmer uncovered over medium-low heat for 20 to 25 minutes, stirring occasionally, until the sauce thickens enough to coat the back of a spoon.

Bring a 6-quart / 5.7 L pot of well-salted water to a boil. Add the pici, stirring gently so strands don't stick, and cook 6 to 8 minutes until tender with a slight chew. Reserve 1 cup of pasta water, then drain.

Add the drained pici directly to the skillet with the sauce. Toss over low heat for 1 to 2 minutes, adding splashes of pasta water until the sauce clings to the strands.

Stir in the torn basil and black pepper. Plate and top with grated pecorino if using. Serve right away.