For the pudding mix, whisk together the sugar, cornstarch, milk powder and salt in a medium bowl, then set aside.

Split open the vanilla beans and use the back of a knife to scrape out the seeds. Add the seeds to the sugar mixture, then whisk well to evenly combine, using a fork or the back of a spoon to break up any chunks of vanilla bean seeds.

Cut the empty vanilla bean pods into thirds, then place in a lidded airtight container with the sugar mixture. Seal the lid, then shake vigorously to distribute the vanilla bean pieces. Store in a cool, dry place until ready to use.

To make the pudding, combine 2 cups milk with 1⁄2 cup of the instant pudding mix in a medium saucepan. whisking constantly over high heat. Bring to a boil, then immediately reduce heat to a simmer and continue whisking for 3–5 minutes, until mixture thickens and coats the back of a spoon.

Let pudding rest at least 5 minutes before serving. Store in an airtight container in the refrigerator.