Heat oven to 400°F. Toss together all crouton ingredients in small bowl. Place onto ungreased baking sheet. Bake, stirring once, for 7 to 10 minutes or until browned. Set aside.
Melt 1/2 cup butter in 3-quart saucepan. Add onion, carrots and undrained oysters. Cook over medium heat, stirring occasionally, until edges of oysters curl and vegetables are crisply tender (8 to 10 minutes). Remove oysters and vegetables with slotted spoon; set aside.
Gradually whisk flour into liquid in pan until smooth. Continue cooking until bubbly (1 to 3 minutes). Gradually stir in milk, cream, salt and 1/4 teaspoon pepper. Continue cooking, stirring occasionally, until mixture comes to a full boil (10 to 12 minutes). Add oysters and vegetable mixture. Continue cooking until heated through (2 to 3 minutes).
To serve, ladle soup into individual bowls; sprinkle with croutons and cracked pepper.