Cook the penne pasta to al dente according to the package directions

Melt the butter and garlic in a skillet

Add the flour and whisk constantly, for 1 minute

Stir in the vegetable broth and heavy cream, until thickened (around 5 minutes), stirring often. Do not let it boil as this will burn the sauce

Stir in the parmesan cheese until melted

Stir in the cooked penne pasta

Salt and pepper to taste and serve immediately