Preheat the oven to 350 degrees F. Butter a 1½ quart baking dish. Take out a larger pan and be prepared to add about 1 inch of hot water in that dish when ready to bake. This will be the "water bath" for baking your bread pudding. The larger dish must be large enough to contain the baking dish you're using for the bread pudding.
In a small saucepan heat the milk and cream together. Set aside to cool slightly.
In a medium bowl, combine and whisk together the egg yolks, maple syrup, and salt. Very gradually whisk the milk mixture into the egg mixture. You don't want to scramble the eggs with hot milk, so do this slowly!
In a separate bowl, use a hand mixer to beat the egg whites to stiff-peak stage (not dry). Fold the beaten egg whites into the egg custard mixture.
Spread the bread cubes evenly in the prepared dish. Pour the egg custard mixture over the bread cubes and sprinkle nutmeg lightly on top. Place the baking dish in a larger pan filled with about 1 inch of hot water. You want enough water in the larger dish so the water comes up about halfway on the bread pudding baking dish when it's set into the water bath.
Bake 40 to 45 minutes, or until a knife inserted into the center comes out clean.