Wipe out the same pot you used to cook the pasta and filling. That is what I love about this dish – 3 steps, but 1 pot. Less cleanup afterwards! Melt the butter over medium-high heat. Once it’s melted, whisk in flour and continue to whisk until it’s smooth and fully incorporated. Cook for an additional 1-2 minutes, to cook off any flour flavor. You want the flour the thicken the sauce, but not add flavor. Add the milk about ½ cup at a time, whisking constantly to prevent lumps. Once all the milk is added, add the garlic and bring the sauce to a boil, stirring frequently. The sauce will immediately begin to thicken once it boils. Reduce the heat to medium, and simmer for 2-3 minutes. Stir in the ricotta, lemon juice, salt and pepper. Taste and adjust seasoning, adding more lemon juice, salt or pepper.