A deeply comforting oven-baked mac and cheese celebrates a mix of melty, sharp, and tangy cheeses, all perfectly balanced with a crisp, buttery breadcrumb topping.
6 tablespoons unsalted butter, divided
12 ounces elbow macaroni
1 cup finely chopped yellow onion
2 tablespoons all-purpose flour
2 cups whole milk
3/4 teaspoon kosher salt
1/2 teaspoon black pepper
1/8 teaspoon cayenne pepper
1 cup Gouda cheese, shredded (about 1 cup)
4 ounces mozzarella cheese, shredded (about 1 cup)
2 ounces blue cheese (about 1/2 cup)
4 ounces sharp cheddar cheese, shredded (about 1 cup)
1 cup fresh breadcrumbs
Preheat oven to 375°F. Grease a 2-quart baking dish with 1 tablespoon butter. Bring a large pot of generously salted water to a boil over high. Add macaroni; cook until al dente, about 8 minutes. Drain in a colander; rinse under cold water to stop the cooking process, and let drain completely.
Melt 3 tablespoons butter in a medium saucepan over medium-low. Add onion; cook, stirring often, until translucent, about 5 minutes. Sprinkle in flour; cook, stirring constantly, for 3 minutes. Gradually whisk in milk, and bring to a gentle simmer over medium; cook, whisking constantly, until thickened, 5 minutes. Stir in salt, black pepper, and cayenne pepper. Add Gouda, mozzarella, and blue cheeses; cook, stirring constantly, until almost melted, about 1 minute. Remove from heat; fold in cooked macaroni.
Transfer macaroni mixture to prepared baking dish; sprinkle evenly with cheddar and breadcrumbs. Microwave remaining 2 tablespoons butter on low until melted, about 1 minute; drizzle evenly over breadcrumbs.
Bake, uncovered, until casserole is bubbling and topping is crisp and golden brown, about 25 minutes. Let stand for 10 minutes before serving.
