Martha's Macaroni and 3 Cheeses
- Preheat oven to 400 degrees. Bring a large pot of water to boil. Butter a shallow 4 quart baking dish (oval or round 9x13' rectangle . Set aside.
- Generously salt boiling water; add pasta. Cook, according to package instructions, until 2 minutes short of al dente. Drain pasta, and return to pot.
- While pasta is cooking, melt butter in a large saucepan over medium heat. Transfer 2 tbsp melted butter to a small bowl; set aside for topping. Add flour and mustard powder to remaining butter in saucepan. Cook, whisking, for 1 minute. Do not let flour darken. Whisk in milk. Bring to boil; reduce heat to medium low, and simmer until sauce is thickened, 2-3 minutes.
- Remove sauce from heat. Gradually whisk in cheeses; add Worcestershire sauce, and season generously with salt and pepper. Add sauce to pasta, and toss to combine; transfer to prepared baking dish.
- Place dish on a rimmed baking sheet and bake until top is golden and sauce is bubbling, 15-20 minutes (if refrigerated, bake for 30-35 minutes). Cool for 5 minutes before serving.