- Cook the penne pasta according to the package directions. Drain and set aside. 
- In a large skillet, heat olive oil over medium heat. Add the minced garlic and sauté until fragrant, about 1 minute. 
- Add the butter and let it melt completely. Stir in the flour and cook for 1 minute to make a roux. 
- Slowly whisk in the milk and heavy cream until smooth. 
- Season with salt and pepper and cook until the sauce thickens, stirring frequently. 
- Add the parmesan cheese and stir until melted and well combined. 
- Toss the cooked penne pasta into the sauce and stir until coated. 
- Garnish with chopped parsley if using and serve warm.