Spray 11×7-inch non-reactive baking dish with cooking spray. Cut bread into 1-inch cubes to yield about 8 cups; spread evenly in bottom of pan and sprinkle with raisins. Set aside.

In a medium saucepan, heat half-and-half with butter, stirring until butter is melted. Cool for 10 minutes. In a medium bowl, whisk sugar, cinnamon, nutmeg, rum extract and egg substitute together. Then, slowly whisk in butter mixture until well blended. Pour over bread cubes and toss to coat all. Let stand for 1 hour.

Preheat oven to 350°F. Place baking dish with pudding into a larger pan containing 1-inch hot water. Bake for 35 minutes or until mixture is set and sharp knife inserted in center comes out clean. Cool and serve warm, dusted with powdered sugar, if desired.