Wash and dry the fresh produce. Thinly slice the scallions, separating the white bottoms and hollow green tops. Quarter the lime(s). Thinly slice the cucumber(s) on an angle. Place in a bowl; add the juice of 2 lime wedges (or 4 wedges for 4 servings). Stir to coat. Set aside to marinate, stirring occasionally. In a large bowl, combine the dressing and the juice of the remaining lime wedges. Add the cabbage and carrots and sliced green tops of the scallions; season with salt and pepper. Stir to coat.

In a bowl, combine the beef, mushroom duxelles, cornstarch, and sliced white bottoms of the scallions; season with salt and pepper. Gently mix to combine. Form the mixture into 4 patties (or 8 patties for 4 servings), about 1/2-inch thick. In a medium nonstick pan (or large for 4 servings), heat a drizzle of olive oil on medium-high until hot. Add the patties. Cook 2 to 3 minutes per side, pressing down on the patties with a spatula to flatten, or until browned and cooked through. Turn off the heat.

The USDA recommends a minimum safe cooking temperature of 160°F for beef.

Just before serving, wrap the bao buns in a wet paper towel. Arrange on a plate in an even layer. Microwave in 30 second intervals, or until just softened and heated through. Carefully open the buns;spread the hoisin sauce on both sides, then fill each with the marinated cucumber(s)and cooked patties. Serve the finished buns with the slaw on the side. Enjoy!