In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl using an electric hand mixer, combine the sugar, cocoa powder, butter, hot water, vanilla and salt. Increase speed to medium and beat for 1 minute until fully combined.
Add the melted chocolate, beating until fully mixed.
Allow to sit at room temperature for 30 minutes to let it thicken.
Frost your cake or cupcakes using an offset spatula.
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