Bring 2 litres water seasoned with 1 ¾ teaspoon sea salt to boil in a large saucepan. Once the water comes to a boil, add 200 g pasta. Cook until al dente (or according to package instructions), then drain. Reserve the pasta water.
Set a large saucepan over medium heat. Add 2 tablespoons olive oil, and, once hot, add 500 g courgette (sliced into half-moons). Don't overcrowd your pan.
Cook the courgette until slightly charred. Season with 2 teaspoons balsamic vinegar and ½ teaspoon red chilli flakes. Stir to mix the seasonings in and continue cooking until the courgettes have softened and taken on an almost "jammy" texture. Turn off the heat.
Add 20 g pine nuts and 1 clove garlic to a food processor. Process until just coarsely broken, not a paste. Add 30 g basil and 1 tablespoon olive oil. Pulse again, very briefly. Now add half of the cooked courgettes, and blend into the pesto. Finally, grate in 10 g vegetarian hard cheese. Instead of making pesto from scratch (even though it's unbelievably easy!), you can blend the cooked courgettes into leftover pesto or readymade store-bought pesto, instead.
To the same pan as the remaining courgettes, add the drained pasta, the courgette pesto, and a splash of reserved pasta water. Mix well, and adjust seasonings as needed, and serve.