I make this sauce all the time for quick pasta meals. It's the same sauce I use in my Creamy Spinach Pasta.
4 Tbsp Butter
3 Tbsp Flour
1/2 tsp Minced Garlic (= to 2 fresh cloves garlic)
1/2 pint Whipping Cream (about 1 1/2 Cups)
1/4 tsp Kosher Salt
Sprinkle of Parsley if desired, to add color
Melt butter in saucepan and add the flour, mixing until creamy. Slowly add whipping cream while whisking. Add Minced Garlic, Salt, and Parsley if desired. Cook over medium heat continuing to whisk until hot and creamy.