Add both sugars into a saucepan with room temperature water. Whisk and continue to mix together.
Cook on medium heat until it starts to boil while continuing to whisk. Turn the heat to medium-low so that there are still plenty of bubbles. The syrup mixture should be at about 150°F - 160. Now add ½ teaspoon vanilla. Edit: you don’t need to check the temperature!

Remove from heat and allow to cool. Transfer to glass jars or airtight containers. The next morning give a good shake and if it’s too thick add a little more water. You can keep in your pantry or in the fridge.