In a small bowl or measuring cup, combine the cherry syrup (or grenadine), vanilla extract, almond extract, black licorice/anise syrup (or anise extract), orange zest, lemon juice, and prune syrup (if using). Stir thoroughly until uniform. This creates a concentrated flavor blend that approximates the complex notes of Dr Pepper.

Taste the blend: it should be noticeably sweet with cherry and vanilla top notes, a faint almond/anise background, citrus brightness, and a subtle dark-fruit depth. Adjust any single component by drops or 1/8-teaspoon increments if one note is too strong—more cherry for fruitiness, more vanilla for creaminess, more anise very sparingly for spiciness.

Assemble Soda

Fill a tall glass with ice (about 1 cup). Chilling the glass or using very cold ingredients helps preserve carbonation.

Pour the carbonated water (2 cups) into a separate chilled pitcher or measuring cup. Add the cola (1/2 cup) to the carbonated water and stir gently to combine. Stirring gently helps maintain carbonation.

Add the prepared flavor blend to the soda mixture. Start by adding all of the blend from the previous section (the quantities listed were for one serving). Stir gently once to integrate. Do not vigorous stir, to avoid flattening the soda.

Taste the assembled soda. If you desire a stronger Dr Pepper profile, add small increments (1/4 tsp) of the flavor blend or a touch more cola for sweetness. If it's too sweet, add a splash more carbonated water. Balance until it resembles a sweet, cherry-vanilla-amber cola.

Serve & Garnish

Pour the finished soda over the ice in the prepared glass. Allow a small head of foam to settle naturally.

Garnish with one maraschino cherry and an orange slice on the rim or floated in the glass. Optionally, express a bit of orange zest over the top for extra aroma.

Serve immediately while fizzy.