Combine the cream, milk, and sugar in a medium saucepan over medium heat. Wait until the mixture comes to a simmer. Then remove the saucepan from heat.
2. Scrape the vanilla seeds into the milk, add the bean, and allow the mixture to sit for a half hour.
3. Strain into a clean bowl, discarding the vanilla bean. Cover and refrigerate for at least 2 hours or overnight.
4. Get out your ice cream maker! Transfer your gelato mixture into it, then freeze according to manufacturer's directions.
5. As you let the ice cream maker do its work churning the gelato, melt the chocolate in the microwave. Heat it on high for 20 second intervals until it is melted and smooth. Two minutes before churning is finished, drizzle the melted chocolate into the gelato. Alternately, the chocolate may be quickly folded in with a rubber spatula when the gelato is completed.
6. Scoop gelato into bowls or cones. Garnish with a cookie, if desired.