In a medium bowl, beat the egg yolks until they lighten in color. Gradually add 1/3 cup sugar and continue to beat until sugar is completely dissolved.

In a medium saucepan, over high heat, combine the milk, heavy cream, and nutmeg and bring just to a boil, stirring occasionally. Remove from the heat and very gradually pour the hot mixture into the egg and sugar mixture. Return everything to the saucepan and cook until the mixture reaches 160 degrees F. Remove from the heat, stir in the bourbon, pour into a medium mixing bowl, and set in the refrigerator to chill.

In a medium mixing bowl, beat the egg whites to soft peaks. With the mixer running gradually add the 1 tablespoon of sugar and beat until stiff peaks form. Whisk the egg whites into the chilled mixture. Serve chilled. Top with whipped cream and a sprinkling of nutmeg, if desired.