• 1 1/2 cups peeled and diced russet potatoes
• 1 1/2 cups chopped leeks
• 1/2 cup chopped carrots
• 8 tablespoons unsalted butter, divided
• 8 ounces sliced cremini mushrooms
• 2 teaspoons chopped garlic
• 1 cup frozen green peas, thawed
• 2 1/2 tablespoons all-purpose flour
• 1 1/2 cups chicken broth (or reserved strained stock)
• 1/4 cup heavy cream
• 1 tablespoon hot sauce
• 1 10-inch square puff pastry sheet, thawed
• 1 large egg, beaten