Preheat the oven to 350ºF and spray a 9-inch tart pan with nonstick cooking spray.
Prepare the crust: Place the walnuts in a high powered food processor and process the walnuts until they turn into a flour-like consistency.
Add the graham crackers, brown sugar, and cocoa powder to the food processor and pulse until the mixture resembles graham cracker crumbs.
Next, add the cold butter to the food processor and pulse until the mixture turns into a crumble and starts to stick together.
Add the vanilla and kosher salt to the processor and pulse until combined.
Pour the crust ingredients into the greased tart pan. Use your hands to press the crumble evenly on the bottom of the tart pan and then up the sides of the pan.
Place the crust in the oven and bake at 350ºF for 8 minutes.
Remove the crust from the oven and let it cool for 10 minutes. Place the tart crust in the freezer while you prepare the chocolate filling.
Prepare the filling: Add the heavy cream, butter, cream cheese, and vanilla extract to a medium-sized saucepan. Heat the ingredients over low/medium heat, stirring periodically for 7-10 minutes. Make sure to stir the mixture enough that the heavy cream doesn’t scald on the bottom of the saucepan.
When the butter and cream cheese have completely melted and the mixture is thick and creamy, add the chocolate and sugar to the creamy mixture. Turn the heat to medium and stir constantly until the chocolate and sugar are melted and dissolved.
Remove the saucepan from the heat when the chocolate is melted. Add the eggs to the chocolate mixture and whisk until the eggs are completely incorporated.
Pour the chocolate filling into the chocolate graham cracker crust.
Place the tart in the oven and bake for 20-25 minutes or until the tart is jiggly but set.
Remove the tart from the pan and then let cool for 15 minutes.
Carefully remove the sides of the tart pan from the tart and place the tart in the freezer for 30 minutes.
Meanwhile, create chocolate ribbons.
Remove the tart from the freezer and top with desired toppings.
Enjoy!