In a saucepan over medium heat, stir together sugars and water until the sugar has dissolved. Don't let it boil.
Stir in pumpkin purée and vanilla extract until combined. Stir in the spices.
Cook for about 10 minutes total, being careful not to boil. Turn off the heat and let the mixture sit for 15 minutes.
Strain through a fine mesh strainer.
Store in a glass jar for up to 2 weeks.
Notes
Syrup shortcut: Use 1 tablespoon of a pre-made pumpkin pie spice blend instead of cinnamon, ginger, nutmeg, cloves and cardamom. Storage: Store this pumpkin spice syrup in the fridge in a food-safe, airtight container (such as a mason jar). Use within 2 weeks, since fresh pumpkin and spices shorten its shelf life.