- In a large bowl, whisk the vinegar and honey together. Add the broccoli slaw and toss to combine. Season with salt and pepper. Cover and refrigerate.
- In a food processor, pulse the mushrooms until finely chopped. In a large nonstick skillet, heat 1 tbsp oil on medium-high. Add the onion and cook 4 min., until golden. Add the mushrooms and garlic powder and cook 8 min., until liquid has been released and mostly evaporated, stirring often.
- Transfer mushrooms to a large bowl and cool 5 min., until no longer hot. Add the ground beef. Combine and form into four 4-inch patties. Season on both sides with salt.
- Wipe out the skillet and add remaining 2 tbsp oil. Heat on medium-high. Add burgers and cook 3-4 min. per side. Place 1 burger on each bun and top with broccoli slaw.
courtesy of Giant Food Stores