Separate eight of the eggs. Break them one at a time into two cups. If no yolk at all got into the white, pour the white into a small bowl. If any yolk got into the white at all, put that white into a second bowl, which you will also use to collect the yolks. Keep separating until you have 10 clean whites. Put the bowl of whites into the refrigerator. The rest of the eggs can be added to the bowl with the yolks.
Whisk the eggs with the yolks until they begin to get lighter in color. Add the sugar, half-and-half, and vanilla, and whisk to blend completely. This is now your custard.
Slice the bread about an inch thick. Butter a 13-by-9-inch baking dish, and make a shingled layer of the bread slices along the bottom and up the sides. Dust liberally with cinnamon. Sprinkle on about a third of the raisins. Pour about a third of the custard over the bread, enough to soak it and leave some liquid in the gaps.
Repeat the above step twice, to make three or layers. Make sure the bread is well soaked. Leave out some of the bread if necessary to make sure all the bread you use is very wet with custard.
Set the baking dish in a pan of warm water, and bake in the preheated 300-degree oven for about an hour. Remove and cool until lukewarm.
In a completely clean, grease-free bowl, beat the reserved egg whites with cream of tartar at high speed until peaks begin to form. Add sugar a little at a time, followed by vanilla, until completely blended.
Raise oven temperature to 375 degrees. With a rubber spatula, cover the pudding with as thick a layer of meringue as you can. Little swirls and peaks are desirable. Bake in the 375-degree oven until the meringue is browned—three to five minutes. Serve immediately.