Preheat the oven to 350 degrees F.
To make the crust, add the oreos to a food processor and blend until small crumbs remain. Stir the crumbs and melted butter together until all the pieces are moistened.
Press the mixture in to a 4 x 14 inch tart pan. Refrigerate while you make the filling.
Place the chocolate in a bowl. Heat the heavy cream in a saucepan over low heat until it's warmed and just until bubbles appear along the edges of the pan. Pour the cream over the chocolate and let it sit for a minute. After a minute, stir it until a thick and smooth chocolate ganache forms. Whisk in the beaten egg and the vanilla extract. Remove the crust from the fridge. Pour the mixture into the crust.
Bake the tart for 20 to 25 minutes, until the chocolate is just set. Remove it and let it cool completely.
While the tart is baking, heat the pomegranate juice and sugar in a saucepan over medium-low heat, whisk constantly until the sugar dissolves. Let the mixture come to a boil and cook for 2 minutes. Remove it from the heat and let it cool. Pour it into a jar and stick it into the fridge.
Before serving, drizzle the glaze over the crust - as much or as little as you'd like! You will have extra glaze, so you can keep it out for serving if someone wants extra. Cover the top of the tart with pomegranate arils. I like to slice it into wedges to serve!