In a microwave-safe bowl, melt 1/2 cup dark chocolate chips on medium power in 30-second intervals until just melted.
Sift the flour, Cocoa Powder, salt, baking soda, and baking powder together into a large mixing bowl.
In a large mixing bowl beat the butter, brown sugar and granulated sugar until fluffy.
Mix in the egg, then add the vanilla. Add melted chocolate and mix until combined.
Mix in the flour mixture by hand until combined (this avoids a cake-like consistency).
Fold in the chocolate chips.
Spread the dough into the prepared pan and smooth the top. Bake for 30 minutes. After 30 minutes, give the pan a little shake. If it jiggles in the middle, put the pan back in and try again every 5 minutes until there is no longer any jiggle.
Set aside to cool.
For the caramel:
Combine the sugar and syrup in a medium saucepan. Cook on medium heat, stirring constantly until it becomes a light caramel color.
Add the butter, salt & cream stir until smooth. Remove from heat and mix in the vanilla.
Set aside to cool slightly, then pour over the cooled base.
Allow to cool completely.
Melt the chocolate melt chocolate in a microwaveable bowl for 30 seconds at a time (stirring in between) until the chocolate is smooth and fluid.
Pour the melted chocolate over the caramel and set aside until the chocolate has cooled almost completely. Sprinkle with the salt and leave to set completely before cutting.
Cut into squares and serve.
Notes
(for more information on how to properly melt chocolate, see my guide on How to Melt Chocolate).