Preheat oven to 350. Put a kettle of water on to boil.

In a medium-sized bowl, whisk together the eggs, sugar, and salt.

In a small saucepan, heat the milk until scalded (just below the boiling point). You'll see bubbles forming around the edge. Remove the pan from the heat and slowly pour the egg mixture in, whisking all the while. Stir in the vanilla and raisins.

Place the bread, buttered side up, in a 9x9 pan, just fitting in a few layers as evenly as possible. Pour the milk and egg mixture over the bread.

Fill a 9x13 pan (or something else that will hold your 9x9 pan) half full with boiling water. It's easier to slide your oven rack out, put the larger pan on the rack, put the pan with the bread pudding in it in the larger pan, then pour the boiling water in the outer pan so that it comes up to the halfway point of the smaller pan. Slide your rack carefully back into your oven. Close the door and bake for 30 minutes or so, until the custard is set.