Preheat your oven to 350°F (175°C). In a medium bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Mix until well combined.

Press the crumb mixture firmly into the bottom and up the sides of a 9-inch tart pan. Bake in the preheated oven for 10 minutes. Remove from the oven and let cool completely.

In a small saucepan, heat the heavy cream over medium heat until it just begins to simmer. Remove from heat and add the chopped chocolate. Let it sit for 2-3 minutes, then stir until smooth and glossy.

Stir in the vanilla extract into the chocolate ganache. Pour the ganache into the cooled tart shell, spreading it evenly.

Refrigerate the tart for at least 2 hours, or until the ganache is set.

Once set, top the tart with fresh blueberries and dust with powdered sugar before serving.