Mac and cheese with crackers in the oven

Ingredients:

• 450 g of pasta horns
• 110g unsalted butter + melted butter for greasing the pan
• 1/4 cup premium flour
• 2 tsp mustard powder
• 1 teaspoon Worcestershire sauce (optional)
• 1 teaspoon hot sauce
• 1/4 tsp cayenne pepper
• 1 liter of whole milk
• 220 gr. havarti cheese, grated (about 2 cups)
• 450 g sharp yellow cheddar, grated (about 4 cups)
• 12 slices white American cheese, grated (about 3 cups)
• 1 package butter crackers (such as Ritz), crushed (about 35 crackers)
• 2 tbsp grated Parmesan (optional)

Preparation:

1. Preheat oven to 375°F (190°C). Bring a large saucepan of salted water to a boil over high heat. Add the pasta and cook until slightly tender, about 6 minutes. Set aside 1/2 cup of the water, drain the rest, and rinse under cold water.
2. Meanwhile, melt 4 tablespoons butter in a large saucepan over medium heat. Whisk in the flour, mustard powder, Worcestershire sauce, hot sauce, and cayenne pepper and cook, stirring, until smooth and light golden, about 2 minutes. Whisk in the milk and cook, stirring occasionally, until the sauce comes to a simmer and thickens, about 5 minutes. Set aside 1 cup each of the Cheddar and American cheeses and stir the rest into the sauce with the Havarti; cook, stirring, until the cheese is just melted, another 1 minute. Stir in the pasta, adding more of the cooking water if the sauce is too thick. Season with salt to taste.
3. Grease a 9x13-inch baking dish with melted butter. Spread the mac and cheese in the dish. Melt the remaining 4 tablespoons butter in the microwave; toss with crushed crackers and Parmesan. Sprinkle the reserved cheddar and American cheese evenly over the macaroni, then top with the cracker mixture. Cover with foil and bake until heated through, about 25 minutes. Remove the foil and continue baking until golden brown and bubbly, another 20 minutes. Let rest for 10 minutes and serve.