FRENCH ONION MAC-AND-CHEESE

French Onion Mac-and-Cheese image

Provided by Sarah Carey

Time 55m

Number Of Ingredients 14

6 tablespoons unsalted butter, divided
3 onions (1 1/2 pounds total), thinly sliced (about 4 cups)
1 teaspoon chopped fresh thyme, or 1/2 teaspoon dried, plus more leaves for serving
Kosher salt and freshly ground pepper
1/4 cup dry white wine, such as Sauvignon Blanc
1 tablespoon Dijon mustard
1 teaspoon crumbled beef bouillon (from 1 cube; optional)
12 ounces medium shell pasta
1/3 cup unbleached all-purpose flour
3 cups whole milk
1/3 pound Gruyère, grated
1/3 pound fontina, grated
1/3 pound Emmentaler, grated
3 cups torn rustic bread, or 12 slices (each 1/2 inch thick) baguette (about 4 ounces total)

Steps:

Preheat oven to 450°F. Melt 2 tablespoons butter in a large skillet over medium heat. Add onions and thyme, season with salt and pepper, cover, and cook 5 minutes. Uncover and continue to cook, stirring frequently, until onions are golden brown, 15 to 20 minutes (if skillet darkens or onions begin to stick, add a splash of water).
Add wine to skillet, scraping up browned bits from bottom with a wooden spoon. Stir in mustard and bouillon; remove from heat.
Meanwhile, cook pasta in a large pot of salted boiling water until still a bit crunchy, 5 minutes less than package directions. Reserve 1/2 cup pasta water, then drain.
Melt remaining 4 tablespoons butter in same pot over medium-high heat. Add flour and cook, whisking constantly, 1 minute. Gradually whisk in milk and reserved pasta water. Bring to a boil, whisking occasionally, then cook 1 minute.
Remove from heat, mix cheeses together (you should have about 5 cups) and stir in all but 1 cup until melted. Stir in cooked pasta; season with salt. Divide pasta mixture evenly among six 6-ounce ramekins and place on a rimmed baking sheet.
Top evenly with onion mixture, then bread. Bake 7 minutes. Sprinkle with remaining 1 cup cheese and continue baking until bubbly, 6 to 8 minutes more. Garnish with thyme leaves; serve.