Preheat the oven to 350 degrees.
Bring a large pan of salted water to a boil and cook the fusilli until it is al dente. Drain the pasta and run it under cold water.
Roast the red pepper for 20 minutes.
Transfer the roasted peppers to a bowl, cover with plastic wrap, and leave for 10 minutes as this allows the steam to loosen the skin of the pepper.
Remove from the bowl, peel off the skin, and dice the flesh.
Transfer the pasta to a large bowl and mix in the roasted pepper, tomatoes, olives, mozzarella, and basil.
Drizzle generously with olive oil and season with the salt and pepper.