Skillet Macaroni and Cheese
- 6 tablespoons unsalted butter
- 1 cup fresh breadcrumbs
- 1/4 cup grated Parmesan
- 1 small yellow onion, diced small
- 1/2 cup all-purpose flour
- 6 cups 2% milk
- 3/4 pound elbow macaroni
- 3 cups grated sharp white cheddar
- 1 cup grated Gruyere
- 1 teaspoon Dijon mustard
- Salt and pepper
Heat broiler. In a large straight-sided, oven-safe skillet, melt butter. Remove 1 tablespoon butter and combine with breadcrumbs and Parmesan.
Add onion to skillet and cook until softened. Whisk in flour and cook, stirring, 1 minute. Very gradually whisk in milk and bring to a simmer. Add macaroni and cook, stirring constantly and scraping bottom of pan, until tender, about 6 minutes. Remove from heat, stir in remaining cheese and the mustard, and season with salt and pepper. Top with breadcrumb mixture and broil until golden brown, 1 to 2 minutes.