Fill a 9 x 9 x 2 1/2" baking pan with the bread cubes and sprinkle the raisins on top.
(Use enough bread to come to the top of the pan. You might not use the whole loaf).
Whisk the remaining ingredients together to make a batter, pour over the top of the bread and stir lightly. Allow the bread to soak 1/2 hour. The pan will be very full. If you have too much batter, discard the excess. If there's not enough, add a little more milk to the pan.
Bake in a 325° oven for about 40 minutes until the pudding is golden brown and puffed up around the edges. The center should be "set" but still a little soft. You can make this ahead of time and heat it in the microwave oven later.