Place the dried mixed spice blend (cinnamon, clove, nutmeg, about 1/4 tsp) in a small heatproof cup. Pour 1 tablespoon of near-boiling water over the spices and let steep for 5 minutes. Strain and reserve the spiced infusion.

In a small bowl combine the cola flavor concentrate (or 1 tsp very strong brewed black tea if using), cherry extract (1 tsp), almond extract (1/8 tsp), vanilla extract (1/2 tsp), kola nut extract if using (1/4 tsp), and 1 teaspoon of the cooled spiced infusion. Stir thoroughly to make a uniform flavor concentrate.

Sweetening & Acidity

If using high-fructose corn syrup or store-bought cola syrup, measure 1 tablespoon. Alternatively make a quick simple syrup by dissolving 1 tablespoon sugar in 1 tablespoon hot water and cooling. Stir the syrup into the flavor concentrate until fully combined.

Add the phosphoric acid solution (or 1/4 tsp diluted phosphoric acid) to the combined flavor-syrup mix and stir. This adds the characteristic tang; if you prefer to avoid phosphoric acid, substitute with 1/2 tsp freshly squeezed lime juice, but flavor will differ from classic profile.

Assemble the Soda

Fill a tall glass with about 1 cup of fresh ice cubes.

Pour 12 oz (about one can) of well-chilled carbonated water into a separate measuring container (or directly into the glass if preferred). Add the prepared flavor-syrup-acid mixture to the carbonated water. Stir gently once or twice to combine — avoid vigorous stirring to preserve carbonation.

Taste and adjust: if too sweet, add a splash more carbonated water; if too sharp, add a small extra 1/2 tsp syrup. If you used lime instead of phosphoric acid, adjust to taste with a touch more vanilla or cola concentrate for balance.

Finish & Serve

Garnish with a maraschino cherry on top and a lime wedge on the rim if desired. Serve immediately while cold and fizzy.