In your large pot, melt 3 tablespoons of salted butter over medium heat. Once melted, add the finely chopped garlic and sauté for about 1-2 minutes until fragrant. Be careful not to let it burn!
Stir in the dried oregano, dried basil, onion powder, and a pinch of red pepper flakes. Let the spices toast for another minute to release their flavors.
Add 1 pound of penne pasta to the pot along with enough water to cover the pasta (about 4 cups). Season with kosher salt and black pepper to taste. Bring it to a boil and cook the pasta according to the package instructions until al dente.
Once the pasta is cooked, lower the heat and stir in 1 cup of whole milk (or coconut milk) and 1/2 cup of heavy cream (or coconut milk) along with the cream cheese. Mix until the cream cheese is fully incorporated and the sauce is smooth.
Gradually mix in 1 1/2 cups of grated Parmesan cheese, allowing it to melt into the sauce. Stir until the sauce is creamy and coats the pasta beautifully.
Add 3 tablespoons of chopped fresh parsley, the juice from 1 lemon, and 2 cups of baby arugula. Gently fold in the arugula and herbs until just wilted. Adjust seasoning with more salt and pepper if needed.
Serve your One Pot Creamy Penne Alfredo with Spicy Arugula warm, garnished with additional Parmesan cheese and fresh herbs if desired. Enjoy this comforting dish that comes together effortlessly!