<human>:  What is a good recipe for mac and cheese?
<bot>: A good recipe for mac and cheese is to start by preheating your oven to 350°F (175°C). Then boil 2 cups (500 mL) of macaroni in a pot of salted water until al dente. While the pasta is cooking, melt 4 tablespoons (55 g) of butter in a saucepan over medium heat. Once melted, stir in 4 tablespoons (30 g) of all-purpose flour and let cook for 1 minute. Slowly pour in 2 cups (500 mL) of milk, stirring constantly until the mixture thickens. Finally, stir in 2 cups (200 g) of grated cheese, 1/4 teaspoon (1 g) of mustard powder, 1/4 teaspoon (1 g) of garlic powder, then reduce the heat and let simmer for 10 minutes. Once the macaroni is cooked, place it in a sufficient-sized baking dish and pour the sauce over it. Sprinkle the top with extra grated cheese, then place it in the oven for 25 minutes. Enjoy your delicious mac and cheese!