Salmon Turnovers: Reloaded - Alton Brown

Ingredients

• 2 (8 1/2-ounce) sheets frozen puff pastry (Pepperidge Farm is fine)
• 3 cups sliced cremini mushrooms
• 1 tablespoon unsalted butter
• 1/2 teaspoon kosher salt, divided
• 1/2 teaspoon freshly ground black pepper, divided
• All-purpose flour, for dusting
• 2 large eggs
• 14.75 ounce can salmon (preferable wild caught), skin and bones removed
• 3 tablespoons minced cornichons (Don't substitute sweet gherkins!)
• 1 tablespoon juice from cornichon jar
• 2 teaspoons Dijon mustard
• 2 tablespoons chopped scallions (1 large)
• 2 teaspoons chopped parsley