If you’ve spent any time scouring the internet for a recipe that doesn’t result in a grainy, broken mess, you’ve likely stumbled upon Jenn Segal. She’s the classically trained chef behind the massive brand Once Upon a Chef. Her recipes usually work because she tests them like a scientist, and the once upon a chef mac and cheese is arguably her "greatest hit" for families. It’s not just a box of noodles with some powder. It’s a specific, multi-step process that uses a technique many home cooks actually fear: the roux.
Most people mess up mac and cheese. They really do. They buy the pre-shredded bags of cheddar from the grocery store because it's convenient, not realizing those bags are coated in potato starch or cellulose to keep the shreds from sticking together. When that starch hits your heat, it prevents the cheese from melting into a smooth emulsion. You get clumps. You get oil. You get disappointment. Segal’s approach is different because it demands high-quality blocks of cheese and a very specific ratio of fat to flour. It’s the kind of meal that makes you feel like a pro even if you usually burn toast.
The Secret Sauce: It’s All About the Bechamel
The backbone of the once upon a chef mac and cheese is a classic French mother sauce. If you want to get technical, it’s a Mornay sauce, which is just a Bechamel with cheese folded in at the end.
Jenn Segal’s version starts with butter and flour. You cook them together until they smell nutty but haven't turned brown. This is your roux. Then comes the milk. Here is where people panic. If you pour the milk in too fast, you get lumps. You have to whisk like your life depends on it, adding the liquid in a slow, steady stream. It’s a forearm workout. Once that thickens into a silky white sauce, you take it off the heat. That part is crucial. If you add the cheese while the sauce is boiling, the proteins in the cheese will tighten up and squeeze out the fat. That's how you get "oily" mac and cheese.
The blend of cheeses matters too. Segal typically leans on sharp white cheddar and Gruyère. Why Gruyère? Because it has a higher fat content and melts like an absolute dream. It adds a sophisticated, slightly nutty depth that stops the dish from tasting like a kids' menu item.
Why This Recipe Wins Over the "No-Boil" Methods
We’ve all seen those viral TikTok recipes where you throw dry pasta and a block of feta or cream cheese into a pan and bake it. Honestly? They’re okay. But they lack the structural integrity of a real stovetop-to-oven mac.
The once upon a chef mac and cheese relies on boiling the pasta separately—but only until it's extremely al dente. If the pasta is soft when it goes into the cheese sauce, it will turn into mush in the oven. You want it to have a "bite" so it can finish cooking by absorbing that delicious cheese sauce.
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The Topping That Changes Everything
A lot of recipes suggest just throwing more cheese on top. That’s fine if you want a gooey mess, but Jenn Segal advocates for texture. Her signature move involves panko breadcrumbs tossed with melted butter and sometimes a little bit of parmesan.
When this hits the oven, the panko browns into a shattered-glass crispiness. It provides the perfect contrast to the heavy, creamy interior. Without a crunch, mac and cheese is just a bowl of soft things. Boring.
Common Mistakes Most People Make
- Using cold milk: If you pour fridge-cold milk into a hot roux, the temperature shock can cause clumping. Let the milk sit out for twenty minutes or microwave it for thirty seconds.
- Overcooking the pasta: If it’s soft enough to eat comfortably before it goes in the oven, you’ve already lost.
- The "Sharpness" Trap: Extra sharp cheddar is delicious, but the older and sharper the cheese, the less effectively it melts. A mix of "sharp" for flavor and "medium" or Gruyère for meltability is the sweet spot.
- Skimping on salt: Pasta water should be salty like the sea. If the noodles are bland, the whole dish will feel "flat" regardless of how much cheese you use.
Customizing Your Mac and Cheese
While the purist version is legendary, the beauty of the once upon a chef mac and cheese framework is that it’s a blank canvas.
Some people like to add a teaspoon of Dijon mustard to the sauce. It doesn’t make it taste like mustard; it just cuts through the heaviness of the dairy and makes the cheese taste "cheesier." Others swear by a pinch of nutmeg or a dash of cayenne pepper for a subtle back-of-the-throat heat.
If you're feeling fancy, you can throw in some lobster or truffle oil, though honestly, Jenn Segal’s base recipe is so solid it almost feels like an insult to change it.
Is It Healthy?
Let's be real. No. This is a "sometimes" food. It’s loaded with butter, whole milk, and several cups of full-fat cheese. But it’s soul food. It’s the kind of thing you bring to a potluck when you want to be the person everyone asks for the recipe.
Making It Ahead of Time
One of the biggest questions people have about the once upon a chef mac and cheese is whether it survives the fridge. Most mac and cheese recipes turn into a solid, rubbery brick once they cool down.
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Because Segal uses a high ratio of sauce to pasta, this version actually reheats surprisingly well. If you’re making it ahead for a party, undercook the pasta even more than usual. Assemble everything, put it in the baking dish, but don't bake it. Cover it with foil and stick it in the fridge. When you're ready, let it come to room temperature for 30 minutes, then pop it in the oven. You might need to add a tiny splash of milk before baking if it looks too dry, as the pasta will drink up the sauce while it sits.
The Science of the Perfect Melt
There’s a reason why some cheeses work and others don't. It comes down to the pH level and the calcium content.
Cheddar is a "hard" cheese. As it ages, the protein structures become more complex and the moisture content drops. This is why a 5-year aged cheddar won't melt into a smooth sauce—it will just break into oily puddles. By mixing a younger cheese with an aged one, you get the flavor of the old and the chemistry of the young. This is the "secret" to the once upon a chef mac and cheese texture.
Actionable Steps for Your Next Batch
Ready to stop eating the blue box and start making the real deal? Here is how to execute this perfectly.
- Grate your own cheese. Seriously. Buy the blocks of Cabot or Kerrygold and use a box grater. It takes five minutes and changes the entire outcome.
- Mise en place is mandatory. Have your flour measured, your milk ready, and your cheese grated before you turn on the stove. A roux waits for no one. If you're searching for your whisk while the butter is browning, you're going to burn it.
- The "Spoon Test." When making your Bechamel, dip a metal spoon into the sauce. Run your finger down the back of the spoon. If the line stays clear and the sauce doesn't run back into the gap, it’s thick enough.
- Don't over-bake. Most people leave mac and cheese in the oven for 45 minutes. That’s too long. You just want the sauce to bubble at the edges and the breadcrumbs to turn golden. The longer it bakes, the more moisture evaporates, leading to dry noodles.
- Let it rest. Give the dish five to ten minutes out of the oven before serving. This allows the sauce to "set" slightly so it clings to the pasta rather than pooling at the bottom of the bowl.
If you follow these principles, you aren't just making a recipe; you're mastering a technique. The once upon a chef mac and cheese isn't just a meal; it's a reminder that sometimes the old-school, high-effort way of doing things is the only way that actually satisfies.