Christmas Shrub -A Rum Spice Liqueur

Wash the fruits and remove the zest in strips, avoiding the white pith.
Combine the zests, cinnamon sticks, cloves, allspice, vanilla beans, 2 cups of sugar, and 2 cups of water in a large heavy saucepan.
Bring to a gentle boil, then reduce heat to lowest possible setting. Let the ingredients infuse for 30 minutes.
Strain the syrup into a large mixing bowl.
Combine the remaining 1 cup sugar and 1/2 cup water in the same large saucepan.
Cover the pan and bring mixture to a boil. Uncover the pan and cook the mixture over high heat until it turns golden brown or caramelizes -about 5 minutes.
Remove the pan from the heat and let cool 5 minutes.
Add 1 cup of rum to the caramel. BE CAREFUL -the mixture may splatter. When the splatter has subsided, return the pan to low heat stirring with a wooden spoon until the caramel has dissolved into the rum.
Add the caramel mixture and remaining rum to the syrup. (I found a large jar like you see in deli's for pickles I use for this). Whisk or in my case, shake the mixture. Pour into clean bottles or containers. Place in a cool dark place and allow to age. It will keep indefinitely.
I put this is pretty decorative bottles like you see for salad dressing and give as Christmas gifts. I had an uproar the one year I didn't make it.
Servings and yield are approximate, but about 2 gallons I'd guess. This is something you drink like a cordial or as a sipper. It is very strong!