French Onion Mac and Cheese Casserole Recipe

My daughter tried French onion soup for the first time a few weeks ago, and despite being a dedicated cheese lover, she didn’t have positive things to report. “All the cheese is on top, and then there’s soggy bread, and under that nothing but stringy onions.”

It’s not the taste she objects to; it’s the format. I know she’ll love this French onion macaroni and cheese casserole, which transposes the flavors of French onion soup to America’s favorite comfort food (as well as her own). It’s cheesy, gooey, and infused with the sweetness of jammy caramelized onions. Make it for a memorable dinner and keep it in your back pocket when you need an impressive make-ahead casserole.

The Best Combination of Cheeses

French onion soup gets its signature cheesiness from Gruyère, an especially nutty type of Swiss cheese.You can find it with the specialty cheeses. This macaroni and cheese won’t be the same without it.

For creaminess, add a little white American cheese, too. Why American cheese in French onion macaroni and cheese? For years, snobs like me objected to cooking with American cheese, but it’s earned a newfound respect among food science nerds for its ability to work with, ahem, real cheese to make a creamy sauce that won’t break. 

For the Best Caramelized Onions, Don’t Rush

This is a special occasion “cooking to unwind” recipe in part because it’s a time investment. Making caramelized onions happens over low heat and isn’t quick, but for that unmatchable depth of flavor you can’t rush it. As you tend the pan you can do a little prep: measure ingredients, grate the cheeses.

Adding dry sherry at the end helps deglaze all of the flavorful buildup in the pan. The sherry adds its own inimitable, slightly nutty flavor to help echo the Gruyère. 

Tips for Making French Onion Macaroni and Cheese

• Ask for a block of white American cheese from the deli so that you can shred it yourself. It’s a lot easier than cutting up a pack of slices.
• Shred the cheese yourself; pre-shredded blends are coated in starch and don’t melt as smoothly.
• Spiking the sauce with concentrated beef bouillon really pushes this macaroni and cheese into verifiable French Onion territory. It’s worth the investment in a jar, which has plenty of uses (add a dab to soups and stews to create instant beefy intensity).