Heat oil in a large sauté pan. Add garlic, shallots and crushed red pepper. Cook until caramelized and lightly colored.
Pour in corn syrup, vinegar, apple juice, lime zest, lime juice, thyme and bay leaves. Bring to a boil and cook until sauce is reduced to thick syrup, about 20 minutes.
Remove from heat, strain through sieve (makes about 10 ounces). Cool.
Grill shrimp over medium heat until almost done. Drizzle with with glaze. Serve over steamed rice. Garnish with cilantro and fresh mango, if desired. Finish with remaining glaze.