In a greased (2 quart) glass oven-proof baking dish, mix bread and raisins. Beat eggs, sugar, vanilla, and salt until well blended. Set aside.
In a 4-cup glass measuring cup heat milk and butter on HI (max power) 4 1/2 to 5 minutes, or until steaming hot. Gradually stir in egg mixture. Pour over bread and raisins, sprinkle with cinnamon or nutmeg.
Cover with wax paper.
Cook on 50% power (simmer) for 12 to 14 minutes. When cooked, center may be soft, but will set as it cools.
Serve warm or cooled. Add whipped cream, cool whip, or ice cream for an extra treat. Refrigerate leftovers (if any)!