Place saucepan over medium heat and bring to a gentle simmer, stirring occasionally until the sugar fully dissolves (about 4–6 minutes). Avoid boiling aggressively.

Once sugar is dissolved and the liquid is clear, remove from heat and let cool 5 minutes.

Add chosen flavor(s)

Decide which flavor or flavor blend you want: pick one primary flavor (pumpkin spice, almond, vanilla, hazelnut, gingerbread, caramel, or sugar-free vanilla) and optionally a complementary secondary flavor (for example: pumpkin spice + vanilla, hazelnut + caramel, almond + vanilla, gingerbread + caramel).

Measure the flavor concentrates/extracts: generally use 1 teaspoon of extract for each cup of syrup for strong extracts (vanilla, almond, hazelnut, caramel extract). Use 2 teaspoons if using a spice blend like pumpkin spice (or 2 tsp spice + 1–2 tsp canned pumpkin for a more natural pumpkin flavor). For sugar-free liquid sweeteners, start with 1 tsp and adjust after tasting.

While the syrup is still warm but not hot, whisk in the chosen flavorings and 1 pinch of salt. If using a small amount of vodka (1 tablespoon) or food-grade glycerin (1 teaspoon), add them now to improve preservation and mouthfeel.

Taste and adjust: let cool to room temperature and taste a small spoonful. If flavor is too weak, add up to 1/2 tsp more extract or 1/4–1/2 tsp more spice, stir and retaste. For sugar-free variant, balance sweetness with the sugar-free liquid sweetener instead of adding more sugar syrup.

Finish and store

Once flavor is adjusted, transfer the flavored syrup to a clean glass bottle or jar. Seal tightly. If you added alcohol, label and date the jar.

Refrigerate: standard simple syrup flavored with extracts will keep about 2–3 weeks refrigerated. If you used vodka (≥1 tbsp) it may keep 4–6 weeks. For sugar-free vanilla syrups made with sugar substitutes, keep refrigerated and use within 4 weeks.

To use: add 1–2 tablespoons of flavored syrup per 8 oz beverage (adjust to taste). Shake well before each use as some spices may settle.