The best thing is that you can store this caramel sauce in the fridge and use it wherever you crave for a warm drink.
I know hot chocolate must have cocoa butter(chocolate chunks) to differ from hot cocoa. But here I have used only cocoa powder(not chocolate chunks) to get that chocolatey flavor because i don't like my drink too sweet. I only wanted the sweetness from the salted caramel sauce.
If you want you can use both salted caramel sauce and semi-sweet(bitter-sweet) or dark chocolate to sweeten your hot chocolate. I just added few chocolate chunks on the top.