Shrimp in Garlic Sauce

Name: Shrimp in Garlic Sauce
Ingredients: 1 pound large shrimp (21 to 25 shrimp per pound), peeled; 1 egg white; 1/4 cup cornstarch; 1 to 2 tablespoons water; 2 cups plus 1 tablespoon vegetable oil; 1/4 cup chicken broth; 1/4 cup apple cider vinegar; 1/4 cup ketchup; 3 tablespoons black soy sauce; 2 tablespoons dry sherry; 8 garlic cloves, crushed and finely minced; 2 tablespoons finely minced fresh ginger; 5 tablespoons sugar; 1 teaspoon chili paste, or to taste and tolerance; 1/2 cup sliced fresh water chestnuts, optional; 1 tablespoons cornstarch mixed with 3 tablespoons cold water; 1/2 cup sliced scallions, on the diagonal in 1/2-inch pieces