Orange Sesame Glazed Broccoli and Water Chestnuts

Name: Orange Sesame Glazed Broccoli and Water Chestnuts
Ingredients: For the sauce; Zest of one orange; Juice of two oranges (I used navel); 2 teaspoons freshly grated ginger; 1 cup light brown sugar; 1 cup water; 1/4 cup rice vinegar; 1/4 cup soy sauce; 1/4 teaspoon crushed red pepper flakes; 2 cloves garlic, grated; 1/2 teaspoon salt; 2 tablespoons cornstarch mixed with 1/4 cup water to make a slurry; For the broccoli; 8 to 10 cups broccoli florets cut from about two bunches of broccoli; The orange sauce; 8 ounce can of water chestnuts, drained; 2 teaspoons toasted sesame oil; Toasted sesame seeds for garnish