Bring a large pot of salted water to a boil and add the penne pasta. Cook until al dente, about 8-10 minutes. Drain the pasta and save a little pasta water to adjust the sauce later.

In a medium pan over medium heat, melt the butter. Add the minced garlic and sauté for about 1 minute until fragrant, being careful not to let it burn.

Sprinkle in the flour and whisk continuously for 1-2 minutes until slightly golden to create a thick, smooth sauce.

Gradually pour in the warm milk while whisking constantly to avoid lumps. Keep stirring until you have a creamy sauce that begins to thicken, about 3-5 minutes.

Once the sauce has thickened, add salt and black pepper to taste to adjust flavor.

Stir in the grated parmesan cheese and mix until melted and smooth.

Add the cooked penne pasta to the sauce, tossing to coat. If sauce is too thick, add reserved pasta water until desired creaminess is reached.