Preheat the oven to 350 degrees F. Line a cupcake tin with paper liners and set aside

In a medium bowl, add the dark chocolate, cocoa powder and hot coffee together. Mix well until smooth and refrigerate until chilled, at least 30 minutes.

Whisk together the flour, sugar, salt, and baking soda together in a large bowl and set aside.

Take out the chocolate mixture and whisk in the oil and eggs, then mix into the flour until smooth - one or two small lumps are okay.

Fill the cupcake liners ¾ full and bake for about 18 - 20 minutes.

Make the coffee syrup by heating the coffee and sugar together until boiling for about 5 minutes. Allow to cool while the cupcakes bake. While the cupcakes are still hot, brush the tops with the coffee syrup. (You may have some syrup left over). Allow the cupcakes to cool.

Make the ganache by slowly melting the chocolate, then whisking in the heavy cream until fully incorporated. Top the cooled cupcakes with the ganache.

Make the buttercream. Beat the butter until light and creamy. Add the espresso and cocoa powder, then the melted chocolate. Slowly add in the powdered sugar and beat until light and fluffy. Add heavy cream if you want added creaminess (I didn't feel it was necessary). Fit a piping bag with a large open star tip (I believe mine is an Ateco #4 or #5) and fill with the buttercream. Top the cupcakes with the frosting.

Make the caramel. Heat the sugar in medium-low heat until melted. The sugar should liquefy and turn a deep amber. Quickly take off the heat and add the chilled butter and mix until well incorporated. Add the heavy cream. Note: The mixture will bubble a lot once you add the butter, so be careful. Use a spoon to drizzle the caramel over the buttercream. It should easily swirl down the frosting along the grooves on the frosting.

Sprinkle the cupcakes with fleur de sel (I use a vanilla infused fleur de sel from Beanilla). Insert potato chips into the frosting.

Serve immediately, or store in an air tight container at room temperature for up to three days. If not eating right away, do not garnish with potato chips until ready to serve.