1. Croutons: Preheat oven to 325°. Lightly coat bread slices with vegetable oil cooking spray. In small bowl, mix remaining crouton ingredients. Add bread; toss to coat. Spread in a single layer on baking sheet. Bake until croutons are dry and lightly toasted, 10 to 15 minutes. Remove from oven and set aside.
2. Meanwhile, in food processor or blender, combine almonds, garlic, mustard, yeast flakes, soy sauce, lemon juice, water and oil if desired; process until smooth and well blended.
3. To serve, toss together lettuce and croutons. Add dressing and toss to coat. Serve right away.