Mushroom Melt with Caramelized Port Onions

1. Prepare mushroom blend: Combine all ingredients in large saucepot. Saute over medium-high heat, stirring frequently to sweat the mushrooms. When mushrooms become soft and turn gray in color, remove from pot and drain any excess liquid.
2. Spread cooked mushrooms onto sheet trays to cool completely before portioning/vacuum bagging. Reserve liquid to use in other recipes. Makes about 5 cups.
3. Prepare caramelized port onions: Heat oil in a saucepot over medium heat; add onions. Fully sweat the onions until the water has evaporated. As the onions begin to caramelize, stir occasionally to prevent burning.
4. When onions have browned, stir in sugar, port, garlic, salt and pepper, incorporating thoroughly. Continue stirring the mixture frequently. The onions will continue to reduce substantially in volume. Once the mixture has become dark brown in color, remove promptly from the heat. Cool completely before use. Makes about 3 1/2 cups.
5. Assemble sandwich: Toast bread and place 2 slices of cheese on each piece. Heat oil in a large saute pan; add mushroom blend, caramelized port onions and arugula. Mix ingredients until thoroughly incorporated.
6. Divide about 2 ounces of mushroom mixture onto each slice of bread. Put sandwich halves on sheet tray and place in salamander for 45 seconds or until the cheese is completely melted. While hot, put the sandwich together, skewer, cut and plate.

Photo courtesy of National Onion Association