Michael Schlow Burger with Crispy Onions

These oh-so-satisfying burgers with crispy onions, from Michael Schlow, are slathered with horseradish mayo and topped with crispy onions. Enough said.

A Michael Schlow burger topped with cheese and caramelized onions on a white plate with a serving of slaw on the side.

I chose to make this onion-topped, horseradish-slathered “fat boy” Schlow Burger, created by Boston chef Michael Schlow, because it’s the best burger I know how to make. It’s also fairly simple to do at home. I guess the crowd loved it because I won the People’s Choice Award, the top honor of the evening. Grab a cold beer or iced tea with this one and get ready to make a mess—this is not a dainty meal!–Lee Brian Schrager

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Um, we’d say something, but our mouths are too full of grilled burgers dripping with cheese. You understand.

Michael Schlow Burger with Crispy Onions

A Michael Schlow burger topped with cheese and caramelized onions on a white plate with a serving of slaw on the side.
This onion-topped, horseradish-slathered “fat boy” burger was created by Boston chef Michael Schlow. While not the daintiest burger, it's fairly simple to do at home.

Prep 20 mins
Cook 15 mins
Total 35 mins
2 servings
1097 kcal
5 / 2 votes
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For the Michael Schlow burgers

  • 18 ounces 80% lean ground beef
  • 2 tablespoons extra-virgin olive oil
  • Salt and freshly ground pepper
  • 1/4 cup mayonnaise
  • Juice of 1 lemon
  • 2 teaspoons prepared white horseradish
  • 2 thick slices Vermont or English cheddar cheese
  • 2 brioche hamburger buns split and toasted
  • Creamy Coleslaw

For the Crispy Onions

  • 2 cups vegetable oil
  • 1 large onion


Make the crispy onions

  • Pour the oil into a small, deep pot, add the onion, and bring to a boil (yes, a boil) over medium-high heat. Reduce the heat to medium and cook at a very low simmer, turning the onions with a fork every 30 seconds until golden brown, 30 to 40 minutes. Adjust the heat as needed to maintain a low simmer. At this point the onions won’t be crispy. Rest assured, your patience will be rewarded.
  • Remove the onions from the oil with a slotted spoon and place them in a single layer on paper towels. I promise you that after a few minutes, as the caramelized sugars cool and harden, the onions will become deliciously crisp.

Make the Michael Schlow burgers

  • Combine the meat and the oil in a bowl. Season with salt and plenty of black pepper. Divide the meat into two 9-ounce portions and form them into burgers. Cover the burgers and refrigerate until ready to use or up to 1 hour.
  • In a mixing bowl, combine the mayonnaise, lemon juice, and horseradish and season with pepper. Cover and refrigerate until ready to use.
  • Heat a grill to high. Remove the burgers from the refrigerator and let them stand at room temperature for 5 to 7 minutes before grilling. Grill until the burgers retain grill marks, at least 1 1/2 minutes. Give the burgers a quarter turn to mark them and cook for 1 1/2 minutes more. Flip the burgers and cook for another 1 1/2 minutes. Rotate another quarter turn and cook for 1 1/2 minutes more. Transfer the burgers to the top shelf of a gas grill or to a cooler section on a charcoal grill, and cover each with a slice of cheese. If using a gas grill, turn off the heat. Cover the grill. Cook for 4 minutes more, or until the cheese has melted and the hamburgers are rare to medium-rare. (For anything beyond medium-rare, let the burgers sit over indirect heat for longer.)
  • Spread some of the horseradish sauce on each burger. Top each burger with some crispy onions. Season with pepper and then, if you dare, slather more sauce on the top half of the bun and place it on top of the hamburger. Serve the Schlow burgers with the coleslaw on the side.
Print RecipeBuy the South Beach Wine & Food Festival Cookbook cookbook

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Show Nutrition

Serving: 2gCalories: 1097kcal (55%)Carbohydrates: 25g (8%)Protein: 49g (98%)Fat: 88g (135%)Saturated Fat: 25g (156%)Polyunsaturated Fat: 16gMonounsaturated Fat: 38gTrans Fat: 3gCholesterol: 194mg (65%)Sodium: 590mg (26%)Potassium: 800mg (23%)Fiber: 2g (8%)Sugar: 4g (4%)Vitamin A: 35IU (1%)Vitamin C: 17mg (21%)Calcium: 128mg (13%)Iron: 7mg (39%)

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Recipe Testers’ Reviews

This is definitely one to please your family and friends. The burger is simple–juicy and delicious. The toppings, of course, make it special. The crispy onions add a nice and sweet crunch, the coleslaw is sweet and tangy and bring a different crunch, and the horseradish sauce is creamy and spicy to balance the sweetness of everything else. I would make sure that the cheese is an extra-thick slice, otherwise you don’t really get much flavor. I used an English Cheddar (which was pretty sharp) and barely noticed it was there. In addition, the horseradish sauce calls for the juice of 1/2 lemon and it would be better to indicate how many tablespoons. (My lemon was average size and I bet I got 3 tablespoons of juice, which was too much for the mayo and horseradish.) All together, it was fabulous! I will certainly make this again for my family and for guests. The coleslaw recipe is a keeper on its own.

I’ve never mixed olive oil into hamburger meat before, but it made the mixture nice and smooth, which helped form neater patties. It didn’t change the flavor any, and I can’t say if it added any moisture to the finished burger, but it did help get a nice seared crust to the patty. I’d probably add a couple swirls of olive oil whenever I’m making burgers again. I’d rather just make caramelized onions. The horseradish mayo, though, was delicious and went perfectly with the burger and cheese. Definitely slather that sauce everywhere.

Great flavour in a monster burger! I like the simple preparation of the meat—you need high-quality, extra-lean beef for this. I tried one burger with the mayo slathered and would be a bit more conservative in the future. I really wanted to highlight the taste of the onion and Cheddar combination. The toasted buns did a superb job of keeping things from falling apart. Don’t wait too long to eat this burger, as the onions soften fairly quickly.

Depending on the heat of your oil, the crispy onions could take considerably longer to brown, possibly as long as double the advised time. Since they need to cool anyways, prepare everything else after the onions are done. I guessed that they were done when they started to go from light golden to a darker, caramel-y color. The total time for me at a very low simmer was close to 40 minutes.

This burger, with all the suggested toppings, really is the jam. First off, this is one seriously sized burger—9 ounces of meat made for more burger than I could eat, but my husband was quite happy to polish off his while eyeballing my leftovers. I loved the Crispy Onions—they really made this burger sing. We used a lovely extra sharp Cheddar, and the sweet crispiness of those onions really shone with the sharpness of the cheese. Horseradish doesn’t hit the bill in my house, so this was the only thing omitted, but for horseradish lovers, I can see this would be a hit. The coleslaw was also quite delicious, but we both found it a bit on the sweet side. I will make it again, but cut back on the sugar by at least a quarter, and perhaps grate in some carrot. You really can’t go wrong with this burger.

What a sloppy, messy, awesome burger! I had brioche buns from John Ash’s recipe in the freezer, so I was ready to get going and so glad that I did. Everyone was very pleased with this non-dainty meal. I first thought that a 9-ounce patty would be too big to eat, but it was perfect. We loved the tang of the mayonnaise, lemon, and horseradish sauce. We couldn’t really tell the Crispy Onions were there (maybe too much horseradish sauce dripping off?). I couldn’t get the onions to brown even on a simmer without burning them in spots. Cousin Shari’s Coleslaw was sweet, tangy and delicious. The meal was yummy and will be served many times this summer!

Originally published July 13, 2011



  1. Substitute the plain cheddar with naturally apple-smoked cheddar and you get one extra step of flavor here. Good recipe.

  2. 5 stars
    Made these last night on a grill pan and they were fantastic! I was skeptical about the onions, but they didn’t disappoint and that horseradish sauce with the lemon juice really complements the beef. This simple burger with olive oil added has now become the standard by which all my future burgers will be made. You’ve got a fan in me! Thanks

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