In a medium size saucepan, combine the ingredients. Heat over medium heat, stirring until combined.
Bring to a slow boil, reduce the heat and simmer for 5 minutes – stirring occasionally.
Transfer to a heat proof storage container. Shake well before each use to redistribute the spices.
In a martini shaker, add the rum, gingerbread syrup and eggnog. Fill with ice and shake vigorously for 10 to 15 seconds. Strain into a coupe glass or serve in a rocks glass over ice.
If opting for the gingersnap + meringue garnish, 'paint' the glass with meringue prior to pouring the cocktail. Dip half the glass in the crushed gingersnaps and use the blow torch to brown the meringue on the other half of the glass.
Gingersnap + Meringue Garnish
Place gingersnap cookies in a plastic bag and crush with a mallet or rolling pin. Pour out onto a small flat plate.
For the meringue: In a heatproof bowl, add egg whites sugar and cream of tartar. Place the bowl over a saucepan with two inches of simmering water - the bottom of the bowl should not touch the water. Whisk the egg whites constantly until the sugar is dissolved, about 4 to 5 minutes.
Transfer the egg white mixture to a standing mixer fitted with a whisk attachment. Add the vanilla extract and whip the egg whites on high until stiff peak form, about 5 to 6 minutes.
The meringue recipe is my go to, but it does make a fair amount. The leftover meringue can be made into cookies.
Meringue Cookies: Transfer leftover meringue to a piping bag and pipe onto a baking sheet fitted with parchment paper. Bake in a preheated 300°F oven for 20 to 25 minutes.