Make the base: In a small saucepan, combine sugar and water. Add a pinch of salt if using. Warm over medium heat, stirring until the sugar fully dissolves and the liquid looks clear. Do not boil hard—gentle steam is enough.

Add flavor: Vanilla: Stir in vanilla extract off heat. If using a vanilla bean, add it to the water and sugar as they heat, simmer 3–5 minutes, then remove from heat, cover, and steep 10 minutes. Strain.

Hazelnut (with extract): Remove from heat and stir in hazelnut extract.

Hazelnut (with nuts): Add crushed toasted hazelnuts to the hot syrup, cover, and steep 20–30 minutes. Strain through a fine sieve or coffee filter.

Mocha: Whisk cocoa powder with a few tablespoons of warm syrup in a bowl to make a smooth paste. Return paste to the pot and whisk until glossy. Add vanilla and a pinch of salt.

Cinnamon: Simmer cinnamon sticks in the syrup for 5 minutes, then remove from heat and steep 15 minutes. Strain and add vanilla if using.

Peppermint: Stir in peppermint extract off heat. Start with less and taste—peppermint gets strong quickly.

Caramel: In a clean, dry saucepan, heat 1 cup sugar over medium, stirring only as it melts and turns deep amber. Carefully pour in ¼ cup water (it will sputter), whisk smooth, then add remaining ¾ cup hot water gradually. Simmer 1–2 minutes, add vanilla and salt.

Adjust thickness: For a slightly thicker syrup, simmer 1–2 extra minutes. For a thinner syrup, whisk in a tablespoon or two of hot water.

Cool and bottle: Let the syrup cool to room temp. Funnel into a clean, airtight glass bottle or jar. Label with the flavor and date.

Use: Start with 1–2 tablespoons per 8–12 ounces of coffee, then adjust to taste. Great in lattes, cold brew, americanos, hot cocoa, and Italian sodas.