Place the vanilla beans on a cutting board. Using a small, sharp knife, slice each bean lengthwise to split it open. Gently press each bean flat and use the back of the knife to scrape out the seeds. Collect both the seeds and scraped pods in a small bowl.

In a small saucepan, combine the sugar, 1/2 cup water, and all of the vanilla seeds and pods. Stir to combine, then place over medium heat and warm gently, stirring occasionally, until the sugar dissolves and the mixture just begins to steam.

Reduce the heat to low and let the mixture simmer very gently for 10–15 minutes, until lightly golden and very aromatic. Stir occasionally and scrape down the sides of the pan to prevent crystallization. The syrup should remain pourable.

Turn off the heat. Using tongs, remove the vanilla pods and set them aside. Stir in the light corn syrup or glycerin until the mixture is smooth and fully combined.

Carefully pour the warm mixture into a blender or food processor. Add the vanilla pods back in. Blend on low, then medium, until the pods are broken into small bits and the mixture looks speckled and slightly thick. If your blender struggles, cut pods into smaller pieces first.

In a small bowl, whisk the cornstarch or arrowroot with 2 tablespoons cool water to make a smooth slurry. Return the blended vanilla mixture to the saucepan over low heat and gradually whisk in the slurry. Cook, whisking constantly, for 3–5 minutes, until it thickens to a loose jam or molasses-like consistency and coats the back of a spoon. Remember it will thicken further as it cools.

Remove the pan from the heat and stir in the pure vanilla extract. Let the paste cool completely to room temperature, then transfer to a clean, dry glass jar with a tight-sealing lid. Store in the refrigerator.

Use vanilla bean paste in place of vanilla extract in most recipes. As a guideline, 1 teaspoon vanilla paste is approximately equal to 1 teaspoon vanilla extract. Start with slightly less in delicate desserts and adjust to taste.