Whisk the granulated sugar and cornstarch together thoroughly in a large, heavy bottomed saucepan. When it is evenly combined, use the whisk to add in the vanilla bean seeds. Whisk in the cream and milk until even, then add the vanilla bean itself. Place the pan over medium heat and whisk constantly until the mixture thickens and bubbles around the edges. Sprinkle the instant coffee granules over the top and whisk in until evenly coloured. Pour the mixture into a heatproof bowl, cover, and refrigerate until chilled completely through, at least 4 hours but probably closer to 8.

Remove the vanilla bean pod from the mixture, give it a quick stir, and pour into your ice cream maker. Freeze according to manufacturer's instructions. If your ice cream maker doesn't have a gelato setting, simply pull the ice cream from the machine when it is soft serve consistency.

While the gelato is turning, melt the chocolate gently in the microwave at half power, stirring after every 30 second burst. When it is fully liquid, transfer to a zipper top bag or an icing bag and zip the bag or twist tie the bag shut. You want the chocolate to remain fluid, but just barely be warm enough to be that way.

Scrape the gelato into a medium mixing bowl set over a larger bowl full of ice. Snip the very tip of the zipper top or icing bag off and quickly drizzle the chocolate over the gelato while stirring or whisking vigorously. As the chocolate hits the gelato, it firms up quickly. The action of the spoon breaks it up into tiny flakes that are dispersed throughout the gelato. You can serve immediately for a soft-serve consistency. For a more traditional gelato texture, scrape the finished gelato into a container and freeze for at least 4 hours before serving.