Cover raisins with water and orange juice. Soak while preparing other ingredients, or cover and refrigerate up to 24 hours.
In a saucepan, heat milk, half and half, and butter but do not allow to boil. Cool slightly.
Combine brown sugar, cinnamon, and nutmeg. Reserve 2 tablespoons of brown sugar mixture for sprinkling on top later.
In a separate saucepan, add the remaining brown sugar mixture, vanilla, and eggs. Whisk until smooth.
Pour heated milk mixture into sugar mixture. Add baking powder and whisk until smooth.
Place 1/2 of bread cubes in a 2-quart casserole dish.
Thoroughly drain raisins and discard soaking liquid. Spread 1/2 cup raisins over the bread.
Top with rest of bread cubes. Sprinkle remaining raisins on top.
Pour the milk mixture over the bread until the bread is saturated. Let stand for 5 minutes.
Sprinkle reserved 2 tablespoons of sugar mixture over top.
Place bread pudding dish in a larger pan. Carefully, add very hot water to larger pan to within 1/2 inch of tops of casserole dish. Bake at 350F degrees for 1 hour 10 minutes to 1 hour 20 minutes or until knife comes out clean when inserted 1 inch from rim.