1

Combine barley and 2 1/4 cups water in a medium saucepan. Set pan over high heat and bring to a boil. Reduce heat to low, cover and cook until all liquid is absorbed and barley is tender, about 40 minutes.

2

Meanwhile, coat a large nonstick skillet with cooking spray and set pan over medium-high heat. Add mushrooms and cook until mushrooms are tender and all liquid evapourates, about 5 to 7 minutes. Transfer mushrooms to a food processor or large bowl.

3

When barley is finished cooking, add to food processor with mushrooms. Add egg, sage, salt and pepper. Pulse on and off, or mash with a fork, until well blended.

4

Shape mixture into 4 equal patties, about 1-inch-thick each. Transfer patties to a plate, cover with plastic and refrigerate for 20 minutes (and up to 24 hours).

5

Preheat broiler. Coat a large baking sheet with cooking spray.

6

Place burgers on prepared baking sheet and broil until golden brown on both sides, about 5 minutes per side. (Note: To grill burgers on an outdoor grill and prevent them from falling through grate, first cover grill grates with foil and then poke some holes in foil to let out smoke.)

7

Meanwhile, in a small bowl, combine sour cream and horseradish. Mix until well blended.

8

Serve each burger with 2 tablespoons of horseradish cream spooned on top.