Preheat the oven to 350 degrees F. Place the tart pan on a large sheet pan and lightly grease the tart pan with nonstick spray.
Blend the teddy grahams until they are finely crushed in a blender or food processor. Toss the crumbs (have the kids measure to make sure you have 1 full cup), melted butter, and white sugar in a bowl. Mix until well combined and then press evenly onto bottom and 3/4 inch up side of the tart pan.
Bake for 8 minutes and then cool on a cooling rack for 15-20 minutes.
For the Fudge Layer, add the heavy cream to a large microwave safe bowl. Bring barely to a boil in the microwave watching it carefully. Pour it over the chopped chocolate (set aside in another heat proof bowl) and let stand 5 minutes. Gently stir until smooth. Whisk together eggs, sugar, salt and vanilla in another bowl.
Slowly add the chocolate and cream mixture to the egg mixture whisking constantly until the mixture is well blended. You don't want to add the chocolate when it's too hot or add it too fast or it will cook those eggs!
Pour the filling into the prepared crust being careful to not overfill. Place the tart (still on the sheet pan) in the oven and bake for 25-28 minutes or until the edges are set and the center is still slightly jiggly.
Remove from the oven and allow to cool completely and then transfer to the fridge and allow to cool until firm; at least 1 hour.
For the ganache, heat the heavy cream to close to a boil (in the microwave) and then add in the chocolate stirring until smooth. Stir in the corn syrup and whisk until completely combined. (Return to the microwave for 10-15 seconds if needed).
Smooth this glaze evenly over the tart and chill for 1 more hour before serving.
Notes
*The total time does not include chilling time of 2 hours.