In a medium saucepan over medium-low heat, cook down the Balsamic Vinegar and Pomegranate Juice until reduced and thickened (about 15-20 minutes). Remove from heat and set aside.
Heat oven to Broil.
Slice Pumpernickel into 4 slices each. Place on baking sheet that has been sprayed with Olive Oil cooking spray. Spritz the top side of the bread with the cooking spray.
Top the bread pieces with ham and thin slices of Gruyere.
Just before serving, broil for 2-3 minutes until cheese is bubbly.
Drizzle with balsamic reduction, and top with Pomegranate arils.