Very gently heat the oil and garlic in
a small pan for a few mins until it just
starts to brown, then add the vinegar.
Bubble for 1 min, then turn off the heat.
When the spaghetti is cooked, reserve
some of the water, then drain. In a large
bowl, toss the spaghetti with the garlicky
oil, spinach, pine nuts and the grated
Parmesan. Add enough water to loosen
everything. Serve in bowls along with the
Parmesan shavings and chilli flakes, plus
more olive oil for drizzling.