Preheat oven to 200C. Line a large baking tray with parchment paper.

Bring a large pot of salted water to a boil. Add the pasta and cook until al dente. Drain, reserving 2 cups of the pasta water, and return the cooked pasta to the pan.

Spread the broccoli florets and garlic out evenly over the lined pan, drizzle with 1 tablespoon of the olive oil. Roast for 18 to 20 minutes or until tender, flipping at the halfway point.

Spread the pepitas out over a small baking tray. Bake for 3 to 4 minutes or until lightly toasted.

Add the roasted broccoli, garlic, pepitas, remaining 2 tablespoons of olive oil, basil, 1/4 cup pasta water, apple cider vinegar, sea salt, and crushed red pepper flakes to a food processor. Pulse several times and then process until you have a coarse pesto, stopping to scrape down the sides as needed. Taste and adjust seasonings.

Spoon the pesto over the pasta and toss to coat, adding pasta water, 1/4 cup at a time, as needed to thin the sauce. Generously season with sea salt and crush red pepper flakes, to taste.