Cook fusilli ( or rotini) in boiling salted water until it’s al dente. Reserve 1 cup (235 ml) of the pasta water before draining.
2. Step
Add basil, garlic, pine nuts, salt, and pepper to a food processor or blender and pulse to start to break up the ingredients. Add water and a splash of the olive oil to get things started.
3. Step
Scrape down the sides of processor bowl to ensure everything is being incorporated evenly.
4. Step
Put the top back on, turn on the food processor, and slowly drizzle the remaining olive oil through the hole on the top of the food processor until emulsified in the sauce.
5. Step
Pour the pesto into a bowl, then stir in the parmesan. (The heat of the food processor will start to melt the cheese, so adding it afterwards retains a nice texture)
6. Step
Drain the pasta and transfer to large bowl or pan.
7. Step
Add pesto and a splash of pasta water, stirring to incorporate.
8. Step
Add parmesan and another splash of pasta water.
9. Step
Top off with more cheese and basil before serving.
