Cook the pasta in a large pot of salted water until al dente, about 10-12 minutes. Reserve 1 cup of the pasta water, then drain.

In a large skillet, heat olive oil over medium heat, add minced garlic and sauté for 1 minute until fragrant.

Pour in heavy cream and half of the reserved pasta water, simmer for 3-4 minutes.

Add broccoli florets, cover, and cook for about 5 minutes until tender-crisp.

Stir in lemon zest, juice, salt, and pepper; add red pepper flakes if desired.

Combine cooked pasta and Parmesan into the skillet, mixing until well coated.