Use metal tongs to hold the sage leaves together arms' length from your body and anything else in the kitchen. Carefully use the cooking torch to gently char the edges of the sage leaves. Do not burn it to a crisp or catch them on fire. Set aside in a heat-safe bowl.
Heat the sugar, corn syrup, and ¼ cup of water over medium low heat until sugar is dissolved. This may take about 5 minutes.
Once the sugar is dissolved, add in the charred sage leaves and turn the heat to medium high. Stir frequently and the syrup with turn a very light amber color. Remove the sage leaves with the tongs, and discard the leaves. After the mixture starts bubbling, about 3-4 minutes, remove from the heat.
Very carefully, add the pinch of salt and stir. Then slowly drizzle in the vanilla extract. it may bubble and spit. While still stirring, very slowly drizzle in the other ¼ cup water. Keep stirring until the consistency is even.
Set aside to cool, then pour into an airtight container. Keeps in the fridge for up to 2 weeks.