Place raisins in a small bowl with the rum and allow to soak.
Remove the crusts from the bread. Determine how much bread you will need by lining the sides bottom and top of a 8 or 9 inch loaf pan and use all the butter to coat both sides of the slices of bread.
Line the sides and bottom with the buttered bread slices and set aside the slices that will go on top.
Pour the milk into a small saucepan and heat it over low heat till you see steam rising when it is stirred - do not boil.
While the milk is heating (keep an eye on it!), put the eggs and 4 T of sugar in the bowl of a mixer. Beat at high speed till the mixture is pale yellow and forms ribbons on the beaters when lifted (about 2-3 minutes).
With the mixer at low speed, slowly add the hot milk. When about half of the milk has been incorporated, you can add the rest more quickly.
Place the almonds and remaining 3 T sugar in a food processor and pulse until the reach the consistency of coarsely ground black pepper. Mix the almond mixture into the custard.
Pour the custard into the bread lined loaf pan, holding back about 1/2 cup.
If the loaf pan fills to the top and you have more than 1/2 cup custard left, it is probably because it is too foamy. Let it stand a bit till it settles.
Take the raisins that have been soaking in the rum and distribute them over the custard in the loaf pan. Save the rum that is left over.
Preheat the oven to 325.
Cover the top of the filled loaf pan with the remaining buttered bread slices and pour the rest of the custard over the layer of bread.
Let stand for about 15 minutes so that the bread becomes well soaked.
Place the bread pudding on the middle rack of the preheated oven and bake till it looks firm with the pan is jiggled, about 40 minutes.
Remove it from the oven and allow it to cool for about 45 minutes to 1 hour.
Once the pudding is cool enough to handle, flip it over onto a flat serving platter. The pudding should unmold easily so that you can remove the loaf pan.
Serve either chilled or at room temperature.
Cut into 1/2 inch slices and sprinkle each serving with a few drops of the left over rum used to soak the raisins.
This can be made up to 5 days ahead and stored in the refrigerator.