This eggnog treat is a whole lot lighter than the norm at 175 calories a serving. It makes a great holiday drink or dessert and is perfectly adaptable for kids and teetotalers: simply leave out the rum. Feel free to cut this recipe in half if serving a smaller group.
Separate the eggs. Put the egg yolks into a mixing bowl and beat with an electric mixer until the eggs go from bright to a more pale yellow, about 1 minute. With the mixer going, gradually add the sugar and mix until it dissolves into the yolks, another minute or so. Add the milk, vanilla, rum (if using) and mix until smooth with no apparent granules of sugar. Pour into a large bowl.
Wash the mixing bowl and beaters so they are immaculately clean and greaseless. Pour the egg whites into the bowl and beat until stiff peaks form. Add the beaten whites to the milk/yolk mixture and use a wire whisk to gently incorporate the two.
If you don’t have access to pasteurized eggs, use the instructions below to make the eggnog in order to minimize the the potential for salmonella: Put the eggs (yolks and whites), sugar, and 1 ½ cups of the milk in a medium sauce pan and whisk well until smooth. Set over medium heat and cook, stirring constantly with a whisk, until the mixture reaches a temperature of 160 °F. It's important not too cook the mixture over too high a heat, otherwise the eggs will effectively scramble. Remove from heat and whisk vigorously until smooth. Pour the mixture into a medium bowl and chill in the refrigerator. Once cold, whisk in the remaining 1 ½ cups milk, vanilla, and rum (if desired). Pour into serving cups and top with frozen yogurt as instructed above. This version yields 8 servings instead of 10 since the eggnog doesn't have the volume of the original recipe.