Step 1

In a Dutch oven, combine the sugar, flour and salt. Gradually whisk in milk until smooth. Cook and stir over medium-high heat until thickened and bubbly, 15 minutes. Reduce heat; cook and stir 2 minutes longer. Remove from the heat.

Step 2

Stir a small amount of hot mixture into eggs; return all to the pan, stirring constantly. Cook and stir over medium heat until mixture is slightly thickened and coats the back of a spoon, 5 minutes.

Step 3

Transfer to a large bowl; cool quickly by placing bowl in ice water and stirring for 2 minutes. Stir in the brandy, rum, bourbon and vanilla. Cool completely. Cover and refrigerate for at least 3 hours. Just before serving, stir in cream and nutmeg. If desired, mix turbinado sugar and ground cinnamon in a small bowl; dip rims of glasses into a shallow dish of water then into the sugar mixture, pressing lightly to adhere. Fill glasses with eggnog and if desired, serve with pirouette cookies.