From ATK
There’s no prescribed method for blended burgers, though the mushrooms are typically parcooked in some way before they’re mixed with the beef and some sources say that the blend should contain at least 1 part mushrooms to 4 parts beef. Wanting to include as many mushrooms as possible, I doubled the mushroom part of the ratio, selecting 8 ounces of ordinary white mushrooms and 1 pound of 80 percent lean ground beef—the same kind I’d select for an all-beef burger. I needed the smaller amount of meat to contribute as much hearty flavor as possible, and lean beef just isn’t as tasty. That’s because much of the meat’s flavor resides in its fat.
I hand-chopped the mushrooms as finely as possible so that they would disappear into the blend and then sautéed and cooled them before folding them and their juices into the beef. I handled the mixture gently, worried that an aggressive touch would toughen the patties. (We know that the more ground meat is worked, the more its myosin—a protein that tightens up upon cooking—develops.)
Recipe
Mushroom-Beef Blended Burgers
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Science: Burgers So Juicy, You Need to “Overcook” Them
If you love your burgers rare, the inside of a mushroom-beef patty won’t look like what you expect. But we guarantee that it’s the most incredibly moist and tender burger you’ll ever eat.
A medium-rare, 100 percent beef burger is succulent because the meat has been cooked to only 125 degrees, so its fibers contract just slightly, squeezing out a small amount of juice. Cooked to a higher temperature, the fibers will tighten up more, sending floods of juice into the skillet. Our blended burgers are different: At 125 degrees, they’re—get this—too juicy. For the best texture, we cook them to at least 135 or even as high as 165 degrees.
Although the beef in blended burgers will shed extra juices at these higher temperatures, the mushrooms, which we precook in the microwave, will not. Mushrooms release some of their water when they’re initially heated, but they still hold on to abundant moisture. When you take a bite of a blended burger, some of their liquid is released, and with continued chewing, even more is wrung out, providing a supremely juicy sensation.
To compare the moisture retention of all-beef and blended burgers, we recorded their pre- and post-cooking weights when cooked to 120, 140, and 160 degrees. In every instance, the all-beef burgers shed more liquid.
After shaping the blend into four big patties and seasoning each with salt and pepper, I seared them in a bit of oil in a skillet until they were deeply browned on the outside and registered about 125 degrees inside. They tasted wonderful: The earthiness of the mushrooms was subtly apparent, but the meatiness of the beef dominated.
What I didn’t expect was how tender—and wet— the burgers would be: They nearly floated in puddles of liquid in the skillet. I was certain that with a little tinkering, I could make the method more efficient, use even more mushrooms without sparing beefiness, and firm up and dry out the patties.
To Mince or Puree, Put Your Finger on the Pulse (Button)
If you place large ingredients such as whole mushrooms in a food processor, hit the “on” button, and let it rip, you’ll have to frequently stop to scrape the sides of the workbowl to nudge the ingredients toward the bottom. That’s because the fast-spinning blades don’t allow big items to fall between them, where they can be cut. Instead, they bounce around atop the whizzing blades. Here’s what to do instead: Start by hitting the pulse button for 1- to 2-second intervals to allow large pieces to fall to the bottom of the bowl during the pauses. As the pieces become smaller, you can pulse faster and faster, finally graduating to leaving the processor steadily on to produce a fine mince or puree.
Making Room for Mushrooms
The whole point of blended burgers is to bulk meat up with mushrooms, so my next move was to further increase the amount of mushrooms to 12 ounces, bringing the mushroom-beef ratio to 3:4. I also switched from a cutting board and knife to a food processor to allow me to rapidly grind the fungi to a thick paste. Some form of parcooking was essential to free the mushrooms of their ample moisture, but rather than relying on the stove, where lots of tending is involved, I popped them into the microwave. After just 3 minutes and a quick stir partway through, the mushroom paste started to boil in its own liquid, so I pulled it out. My next step was crucial: straining off excess juices. Draining away 1/2 cup of mushroom liquid ensured that the burgers cooked up moist but not soggy.
Given the overly tender texture of my first round of burgers, I mixed this batch much more assertively than the last. But the extra stirring didn’t firm them up enough. In fact, the patties were still so soft (they verged on mushy) that my colleagues asked if there was anything I could do to make them a little sturdier.
1. Process raw white mushrooms until they form thick paste resembling cooked oatmeal.
2. Microwave mushrooms until their liquid boils, about 3 minutes, then strain off 1/2 cup of liquid.
3. Process mushrooms with ground beef and salt until mixture pulls away from sides of bowl
