1 pound (450g) elbow macaroni
4 cups, or 1 quart (950ml/32fl oz) milk
1/2 cup (120ml/4fl oz) sriracha
6 tablespoons (85g/3oz) unsalted butter, divided (3/4 stick)
1/2 cup (60g/2oz) all-purpose flour
3 cups (230g/12oz) gruyere, grated
2 cups (225g/8oz) extra-sharp cheddar, grated
1 teaspoon sea salt
1 teaspoon freshly ground black pepper
1/2 teaspoon freshly grated nutmeg
2 tablespoons unsalted butter
2 tablespoons sriracha
1 1/2 cups (170g/6oz) panko (Japanese breadcrumbs)
1. Preheat the oven to 375°F (190°C). Spray a 9 x 13-inch (23 x 33cm) baking dish with baking spray and set aside.
2. Bring a large pot of salted water to a boil. Cook the macaroni according to package directions, or until al dente. Drain well.
3. Heat the milk and sriracha in a medium saucepan over medium heat until hot, but not boiling.
4. Melt the butter in a large saucepan over medium heat. Whisk in the flour, then reduce the heat to low and cook for 2 minutes, stirring constantly. While whisking, add the hot sriracha milk and cook, whisking constantly, for another 4 minutes, or until thickened and smooth.