Falernum, a rum based liqueur flavored with almonds, lime, ginger and cloves. Read about falernum's history in this Smithsonian article.

Falernum Recipe:

16 oz rum (use a mid-grade lightly flavored rum, not the cheap stuff and not a dark rum like Meyers)
Zest from 8 to 9 limes
1" by 2" piece of ginger
1 cup sliced almonds
30 wholes cloves

Optional Spices:
2 teaspoons Allspice berries
1 teaspoon Cinnamon chips
1 piece Star Anise
1 tablespoon Sarsaparilla Root

2 tablespoons citric acid (4 tablespoons of lime juice can be used instead but mixture must be kept in the refrigerator and used quickly.)
Sweetener of choice such as simple syrup, agave syrup, or stevia extract.

Peel the zest form the limes and place in a quart sized jar.  Trim the ginger and slice thin, add to jar. Toast the almonds in a skillet over medium heat or under the broiler, stirring frequently until golden brown.  If using a skillet, shake the almonds in a coarse mesh strainer or colander to remove some of the dust and small flakes since these will burn before the larger slices toast. Add the spices and continue toasting until the spices are fragrant. Add almonds and spices to jar. Add the rum to the jar, tighten lid, and shake to mix.  Let steep overnight, no need to refrigerate.

When the rum mixture is done steeping, strain through a fine mesh strainer. Place almond and zest mixture in a small saucepan with 1 cup of water.  Bring to a low boil and simmer for 5 minutes. Cool, strain, and add liquid to rum mixture, then add citric acid and sweetener. I recommend starting with 1 cup simple syrup (or equivalent of alternate sweetener) and adding more in ¼ cup increments until sweet enough.

This recipe can be altered to use water instead of rum for a non-alcoholic mixer. Use 3 cups of water and place in a sauce pan.  Bring to a boil and simmer for 10 minutes. Strain and add citric acid and sweetener as above.

Since the recipe uses citric acid instead of lime juice, add a splash of lime juice to drinks to bring out the lime flavor.

Our Tiki Mixers Kit has all of the spices you need to start making falernum and other great tiki mixers.