Loaded Mac and Cheese With Spinach

Preheat oven to 350°F. Bring a large pot of water to a boil. When it comes to a boil, salt water. Bring back to a boil and drop in pasta. Cook until al dente. Drain. Transfer to a large bowl and set aside.

Place croutons in a food processor and pulse a few times until they form breadcrumbs.

Make the roux: In a saucepan, melt 4 tablespoons butter over medium heat. Add onion/shallot and cook until soft and translucent, about 5 minutes. Whisk in flour and cook, stirring frequently, until mixture is pale golden and has a slightly nutty aroma, about 2 minutes.

Whisking constantly, slowly pour milk into roux. Continue to whisk constantly over medium heat until sauce has thickened and coats the back of a wooden spoon, about 7 to 10 minutes (if it gets too thick, add a little more milk). Take off heat and add cheese, a handful at a time. Stir to incorporate. Add ground mustard. Add a dash of hot sauce if you like.

Pour sauce over pasta, add spinach and stir to combine. Season with salt and pepper. Transfer mixture to a casserole/baking dish, 10 inches in diameter.

Melt 2 tablespoons butter in a skillet over medium heat. Add bread crumbs and sauté 2 to 3 minutes until golden brown. Scatter breadcrumbs all over the top. Bake 20 to 25 minutes or until hot and bubbling.