In a large pot of boiling, salted water, cook the rigatoni until al dente, about 13-15 minutes.
While the pasta cooks, make the sauce. Melt the butter in a large saucepan over medium-low heat. Add the cream cheese and stir to incorporate as it melts. Add the garlic, garlic powder, dried herbs, salt, and red pepper flakes. Cook for until fragrant, about 1 minute.
Whisk in the broth and bring to a simmer. Simmer for 5 minutes, whisking often, until thickened and smooth. Remove from the heat.
Drain the pasta and reserve a bit of the cooking liquid (to loosen the sauce if needed).
Add freshly grated parmesan and chopped parsley to the sauce and stir to combine. Add the pasta and toss to coat. If the sauce is too thick and isn’t evenly coating the pasta, add a bit of the reserved cooking liquid to loosen it up.
Top with arugula and stir briefly to incorporate. Serve topped with an extra dusting of parmesan and cracked black pepper.
Notes
Storage: Store in an airtight container in the refrigerator for up to 3 days.