Sea scallops with mushrooms and sherry

Ingredients

• 20 large sea scallops (1 1/2 lb), tough ligament removed if attached
• 1/8 tsp black pepper
• 1/2 tsp salt
• 2 tbsp olive oil
• 1/2 stick (1/4 cup) unsalted butter
• 1 pound cremini mushrooms, quartered
• 1/3 cup finely chopped shallots
• 2 garlic cloves, finely chopped
• 2/3 cup medium-dry Sherry
• 1 tbsp balsamic vinegar
• 1 tbsp soy sauce