Mac and cheese is no longer just for the children.
1. Preheat oven to 350 degrees. Butter a 13x9 baking dish.
2. Cook pasta in a large pot of salted, boiling water until tender, but still al dente. Drain and leave in strainer until the sauce is ready.
3. Melt butter in a large saucepan over medium heat. Add flour to make a roux, stirring constantly so flour does not burn.
4. Gradually whisk in milk and cream. Simmer until mixture thickens, whisking constantly. Reduce heat to low and add shredded cheddar cheese (reserving ½ cup for sprinkling on top before baking) and crumbled blue cheese. Whisk until cheese melts, about 2 minutes. Season to taste with salt and pepper.
5. Add cooked pasta to sauce, stirring to coat. Transfer mixture to prepared baking dish and sprinkle with remaining cheddar cheese. Bake until golden brown on top (sauce will begin bubbling), about 25 minutes.