Ingredients (~6-8 servings)

12 oz short pasta (shells, elbows, cavatappi – whatever you have)
4 Tbsp unsalted butter (for onions)
2 tsp olive oil
3 yellow onions, thinly sliced
2 tsp minced fresh thyme
2 Tbsp all-purpose flour
1 1/2 tsp dijon mustard
2 1/2 cups half and half
1/3 cup heavy cream
1/4 tsp freshly grated nutmeg
4 oz white cheddar cheese, shredded by hand
6 oz gruyere cheese, shredded by hand
Kosher salt and pepper to taste

Panko Topping

2 Tbsp unsalted butter
2 tsp chopped fresh thyme
1/2 cup panko crumbs
Salt and pepper

Caramelize the Onions

Melt 4 Tbsp butter with the olive oil in a large Dutch oven over medium heat. Once the butter gets foamy, add all the sliced onions and toss to coat.

Cover the pot and let them cook for 10 minutes until they start wilting down. Remove the lid, lower the heat to medium-low, and add the thyme.

Keep cooking, stirring every so often, until the onions are deeply caramelized – this takes about 40 minutes. They should be golden brown and smell sweet.

Transfer the onions to a bowl and set aside. Don’t wash the Dutch oven – you want that fond for the sauce.

Make the Panko Topping

Melt 2 Tbsp butter in a skillet over medium heat and add the thyme. Cook for ~1 minute until fragrant.

Add the panko and stir to coat everything. Cook for 2-3 minutes, stirring occasionally, until the panko turns golden brown.

Remove from heat, season with salt and pepper, and set aside.

Cook the Pasta and Prep for Baking

Preheat your oven to 425F. Butter a 9×13 inch baking dish.

Bring a large pot of salted water to a boil. Cook the pasta for 2-3 minutes less than the package directions – you want it just shy of al dente since it’ll finish cooking in the oven.

Drain and rinse with cool water to stop the cooking. Let it sit in the colander while you make the sauce.

Build the Cheese Sauce

In the same Dutch oven with the onion fond, melt the remaining 4 Tbsp butter over medium heat. Scrape up any browned bits from the bottom – that’s flavor.

Whisk in the flour and cook for 2-3 minutes to get rid of the raw flour taste.

Slowly whisk in the half and half. Bring to a gentle simmer and cook until thickened – it should coat the back of a spoon.

Stir in the dijon, nutmeg, and heavy cream. Remove from heat and whisk in the cheeses a handful at a time until smooth and completely melted.

Season with salt and pepper to taste.

Assemble and Bake

Fold the caramelized onions and cooked pasta into the cheese sauce. Mix well so everything’s coated.

Transfer to your prepared baking dish and top with the panko mixture.

Bake for 15-20 minutes until the panko is golden brown and the cheese is bubbling around the edges.

Let it rest for 5 minutes before serving – it’ll be molten hot straight from the oven.

French Onion Mac and Cheese