Ingredients
Scale
- 2 pounds sweet onions (Vidalia) or yellow onions, peeled, halved and thinly sliced
- 6 tablespoons of butter, plus more for greasing the pan
- Kosher salt
- 3 tablespoons red wine vinegar
- 2 tablespoons soy sauce
- 1 tablespoon whole grain mustard
- 1 cup of beef broth
- 1 pound of elbow pasta or alternative
- 4 tablespoons of flour
- 3 cups whole milk – you can add 1 cup more if you want a saucier or looser mac and cheese
- 1 pound white cheddar cheese, grated (about 5 cups)
- 12 ounces gruyere cheese, grated (about 4 cups)
Instructions
- Grate the cheddar and gruyere cheese, setting aside 1 cup of gruyere.
- Cut the onions in half, peel them and then thinly slice them.
- In a large pot or sauce pan melt 2 tablespoons of butter over medium heat. Add the onions and ½ teaspoon of salt and saute until golden brown, about 20 minutes. You will need to stir the onions and scrape up any brown bits every few minutes to ensure they do not burn. If the onions look dry you can add a few tablespoons of beef stock. Once the onions are golden brown you will finish them with step 7. If you are note ready to finish them simply turn off the heat until you are ready to resume.
- While the onions are cooking, preheat the oven to 450 degrees
- Cook the pasta in boiling water until 3 minutes shy of al dente (as listed on the package) and then strain. The pasta will cook more in the oven in the cheese sauce which is why you want to undercook it.
- Make the cheese sauce by melting the butter in a medium saucepan over medium heat. Add the flour and let it cook for about 2 minutes. Slowly add the milk while whisking. Once the milk has come to a simmer and thickened add in all the cheese except for the 1 cup of gruyere that you had set aside. Once the cheese is melted into the sauce, turn off the heat.
- The onions should be mostly done and a deep golden brown by now. Add the red wine vinegar to deglaze the pan and scrape up any remaining bits on the bottom. Then add the soy sauce, beef broth and mustard and allow to simmer until the liquid has reduced by half. Turn off the heat.
- Mix the cheese sauce in with the onions and fully combine. Then add in the cooked pasta.
- Transfer the pasta in sauce to a large greased baking or casserole dish and top with the sliced baguette and remaining cup of shredded gruyere cheese.
- Place the baking dish on a sheet pan and bake for 15 minutes until the baguette is toasted and the cheese is bubbling and browned in spots.
- Remove the french onion mac and cheese from the oven and allow to rest for 15 minutes before serving.
Notes
Total Recipe Cost: $25 or $4.16 per serving
- Prep Time: 5 mins
- Cook Time: 40 mins
- Category: Pasta, Comfort Food
- Method: Oven, Stovetop
- Cuisine: American