These Asian-inspired burgers get their irresistible umami flavor from chopped shiitake mushrooms (mixed right into the beef) and a miso-mayo spread. Piled on top, crisp ribbons of bok choy round out the burgers, served with a side of roasted sweet potato wedges.
1. Prepare & roast the sweet potatoes:
Place an oven rack in the center of the oven, then preheat to 450°F. Wash and dry the sweet potatoes; cut lengthwise into 1-inch wedges. Place on a sheet pan. Drizzle with olive oil and season with salt and pepper; toss to coat. Arrange in an even layer, skin side down. Roast 22 to 24 minutes, or until browned and tender when pierced with a fork. Remove from the oven.
2. Prepare the remaining ingredients:
While the sweet potatoes roast, wash and dry the remaining fresh produce. In a bowl, combine the mushrooms and 1 cup of hot water; let stand for at least 10 minutes to rehydrate. Peel and finely chop the garlic; using the flat side of your knife, smash until it resembles a paste (or use a zester). Cut off and discard the root ends of the scallions; thinly slice, separating the white bottoms and green tops. Cut off and discard the root end of the bok choy; thinly slice. Place in a bowl. Drizzle with olive oil and season with salt and pepper; toss to coat. Halve the buns. In a bowl, combine the miso paste and mayonnaise; season with salt and pepper to taste.
3. Prepare Mushroom-infused Beef Patties:
While the sweet potatoes continue to roast, drain the rehydrated mushrooms. Transfer to a cutting board; finely chop. In a large bowl, combine the chopped mushrooms, ground beef, garlic paste, sliced white bottoms of the scallions, and hoisin sauce; season with salt and pepper. Gently mix to combine. Using your hands, form into four 1/2-inch- thick patties. Transfer to a plate.
4. "Sear Beef Patties:
While the sweet potatoes continue to roast, in a large pan (nonstick, if you have one), heat 2 teaspoons of olive oil on medium-high until hot. Add the patties and cook 3 to 4 minutes per side, or until browned and cooked to your desired degree of doneness. Leaving any browned bits (or fond) in the pan, transfer to a plate.
5. Toast Buns in Pan Residue:
Working in batches if necessary, add the buns, cut side down, to the pan of reserved fond. (If the pan seems dry, add a drizzle of olive oil.) Toast on medium-high 30 seconds to 1 minute, or until lightly browned. Transfer to a work surface.
6. Assemble and Enjoy:
Divide the miso mayonnaise, cooked patties, and seasoned bok choy among the toasted buns. Serve the burgers with the roasted sweet potatoes. Garnish the sweet potatoes with the sliced green tops of the scallions. Enjoy!
